diff --git a/.ci/phpstan.neon b/.ci/phpstan.neon
index 17114856a7..a7ea28a1f6 100644
--- a/.ci/phpstan.neon
+++ b/.ci/phpstan.neon
@@ -34,10 +34,6 @@ parameters:
   reportUnmatchedIgnoredErrors: true
   ignoreErrors:
     # these are actually interesting but not right now:
-    - identifier: greater.alwaysTrue
-    - identifier: function.alreadyNarrowedType
-    - identifier: booleanNot.alwaysTrue
-    - identifier: property.phpDocType
     - identifier: nullCoalesce.offset
     - identifier: nullCoalesce.variable
     - identifier: larastan.noUnnecessaryCollectionCall
diff --git a/app/Api/V1/Controllers/Controller.php b/app/Api/V1/Controllers/Controller.php
index 1e992d34be..d47b28be00 100644
--- a/app/Api/V1/Controllers/Controller.php
+++ b/app/Api/V1/Controllers/Controller.php
@@ -62,6 +62,7 @@ abstract class Controller extends BaseController
     use DispatchesJobs;
     use ValidatesRequests;
     use ValidatesUserGroupTrait;
+    protected array $acceptedRoles = [];
 
     protected const string CONTENT_TYPE      = 'application/vnd.api+json';
     protected const string JSON_CONTENT_TYPE = 'application/json';
diff --git a/app/Api/V1/Requests/AggregateFormRequest.php b/app/Api/V1/Requests/AggregateFormRequest.php
index 5398623a2b..7eec75145a 100644
--- a/app/Api/V1/Requests/AggregateFormRequest.php
+++ b/app/Api/V1/Requests/AggregateFormRequest.php
@@ -36,6 +36,8 @@ abstract class AggregateFormRequest extends ApiRequest
      */
     protected array $requests = [];
 
+    protected array $acceptedRoles = [];
+
     #[Override]
     public function initialize(
         array $query = [],
diff --git a/app/Api/V1/Requests/Models/AvailableBudget/Request.php b/app/Api/V1/Requests/Models/AvailableBudget/Request.php
index e3824e40e6..73f419d8ed 100644
--- a/app/Api/V1/Requests/Models/AvailableBudget/Request.php
+++ b/app/Api/V1/Requests/Models/AvailableBudget/Request.php
@@ -39,6 +39,7 @@ class Request extends FormRequest
 {
     use ChecksLogin;
     use ConvertsDataTypes;
+    protected array $acceptedRoles = [];
 
     /**
      * Get all data from the request.
diff --git a/app/Console/Commands/Correction/CorrectsInvertedBudgetLimits.php b/app/Console/Commands/Correction/CorrectsInvertedBudgetLimits.php
index 2574a2891c..aff0cc704a 100644
--- a/app/Console/Commands/Correction/CorrectsInvertedBudgetLimits.php
+++ b/app/Console/Commands/Correction/CorrectsInvertedBudgetLimits.php
@@ -69,10 +69,6 @@ class CorrectsInvertedBudgetLimits extends Command
             $budgetLimit->saveQuietly();
         }
 
-        if ($set->count() > 0) {
-            // FIXME here be a available budget event.
-        }
-
         if (1 === $set->count()) {
             $this->friendlyInfo('Corrected one budget limit to have the right start/end dates.');
 
diff --git a/app/Console/Commands/Upgrade/RemovesDatabaseDecryption.php b/app/Console/Commands/Upgrade/RemovesDatabaseDecryption.php
index b6b741e58e..92c719a648 100644
--- a/app/Console/Commands/Upgrade/RemovesDatabaseDecryption.php
+++ b/app/Console/Commands/Upgrade/RemovesDatabaseDecryption.php
@@ -127,7 +127,7 @@ class RemovesDatabaseDecryption extends Command
         }
 
         // A separate routine for preferences table:
-        if ('preferences' === $table && is_string($value)) {
+        if ('preferences' === $table) {
             $this->decryptPreferencesRow($id, $value);
 
             return;
diff --git a/app/Exceptions/IntervalException.php b/app/Exceptions/IntervalException.php
index 68664388a9..85711d8716 100644
--- a/app/Exceptions/IntervalException.php
+++ b/app/Exceptions/IntervalException.php
@@ -36,7 +36,7 @@ final class IntervalException extends Exception
     public array       $availableIntervals = [];
     public Periodicity $periodicity        = Periodicity::Monthly;
 
-    /** @var mixed */
+    /** @var string */
     protected $message                     = 'The periodicity %s is unknown. Choose one of available periodicity: %s';
 
     public function __construct(string $message = '', int $code = 0, ?Throwable $previous = null)
diff --git a/app/Repositories/Budget/AvailableBudgetRepository.php b/app/Repositories/Budget/AvailableBudgetRepository.php
index 253987eaed..6065955379 100644
--- a/app/Repositories/Budget/AvailableBudgetRepository.php
+++ b/app/Repositories/Budget/AvailableBudgetRepository.php
@@ -389,17 +389,13 @@ class AvailableBudgetRepository implements AvailableBudgetRepositoryInterface, U
             return (string) $budgetLimit->amount;
         }
         // if budget limit period is inside AB period, it can be added in full.
-        if (!$limitPeriod->equals($availableBudgetPeriod) && $availableBudgetPeriod->contains($limitPeriod)) {
+        if ($availableBudgetPeriod->contains($limitPeriod)) {
             Log::debug('This budget limit is smaller than the available budget period.');
 
             return (string) $budgetLimit->amount;
         }
 
-        if (
-            !$limitPeriod->equals($availableBudgetPeriod)
-            && !$availableBudgetPeriod->contains($limitPeriod)
-            && $availableBudgetPeriod->overlapsWith($limitPeriod)
-        ) {
+        if ($availableBudgetPeriod->overlapsWith($limitPeriod)) {
             Log::debug('This budget limit is something else entirely!');
             $overlap = $availableBudgetPeriod->overlap($limitPeriod);
             if ($overlap instanceof Period) {
diff --git a/app/Repositories/UserGroup/UserGroupRepository.php b/app/Repositories/UserGroup/UserGroupRepository.php
index 06f9c47689..8e80a96c89 100644
--- a/app/Repositories/UserGroup/UserGroupRepository.php
+++ b/app/Repositories/UserGroup/UserGroupRepository.php
@@ -255,7 +255,7 @@ class UserGroupRepository implements UserGroupRepositoryInterface, UserGroupInte
             // if there are no other owners and the current users does not get or keep the owner role, refuse.
             if (
                 0 === $ownerCount
-                && (0 === count($data['roles']) || count($data['roles']) > 0 && !in_array(UserRoleEnum::OWNER->value, $data['roles'], true))
+                && (0 === count($data['roles']) || !in_array(UserRoleEnum::OWNER->value, $data['roles'], true))
             ) {
                 Log::debug('User needs to keep owner role in this group, refuse to act');
 
diff --git a/app/Rules/Account/IsValidAccountTypeList.php b/app/Rules/Account/IsValidAccountTypeList.php
index d2a8d97c51..a565a3a59b 100644
--- a/app/Rules/Account/IsValidAccountTypeList.php
+++ b/app/Rules/Account/IsValidAccountTypeList.php
@@ -41,9 +41,6 @@ class IsValidAccountTypeList implements ValidationRule
         if (is_string($value)) {
             $values = explode(',', $value);
         }
-        if (!is_array($values)) {
-            $fail('validation.invalid_account_list')->translate();
-        }
         $keys   = array_keys($this->types);
         foreach ($values as $entry) {
             if (!in_array($entry, $keys, true)) {
diff --git a/app/Rules/TransactionType/IsValidTransactionTypeList.php b/app/Rules/TransactionType/IsValidTransactionTypeList.php
index 1acf81c4d9..8a49bf4c00 100644
--- a/app/Rules/TransactionType/IsValidTransactionTypeList.php
+++ b/app/Rules/TransactionType/IsValidTransactionTypeList.php
@@ -41,9 +41,6 @@ class IsValidTransactionTypeList implements ValidationRule
         if (is_string($value)) {
             $values = explode(',', $value);
         }
-        if (!is_array($values)) {
-            $fail('validation.invalid_transaction_type_list')->translate();
-        }
         $keys   = array_keys($this->transactionTypes);
         foreach ($values as $entry) {
             if (!in_array($entry, $keys, true)) {
diff --git a/app/Support/Http/Api/ValidatesUserGroupTrait.php b/app/Support/Http/Api/ValidatesUserGroupTrait.php
index 0a920c3e2f..c494ab4c32 100644
--- a/app/Support/Http/Api/ValidatesUserGroupTrait.php
+++ b/app/Support/Http/Api/ValidatesUserGroupTrait.php
@@ -89,16 +89,15 @@ trait ValidatesUserGroupTrait
             throw new AuthorizationException((string) trans('validation.belongs_user_or_user_group'));
         }
         Log::debug(sprintf('validateUserGroup: validate access of user to group #%d ("%s").', $groupId, $group->title));
-        $roles       = property_exists($this, 'acceptedRoles') ? $this->acceptedRoles : [];
-        if (0 === count($roles)) {
+        if (0 === count($this->acceptedRoles)) {
             Log::debug('validateUserGroup: no roles defined, so no access.');
 
             throw new AuthorizationException((string) trans('validation.no_accepted_roles_defined'));
         }
-        Log::debug(sprintf('validateUserGroup: have %d roles to check.', count($roles)), $roles);
+        Log::debug(sprintf('validateUserGroup: have %d roles to check.', count($this->acceptedRoles)), $this->acceptedRoles);
 
         /** @var UserRoleEnum $role */
-        foreach ($roles as $role) {
+        foreach ($this->acceptedRoles as $role) {
             if ($user->hasRoleInGroupOrOwner($group, $role)) {
                 Log::debug(sprintf('validateUserGroup: User has role "%s" in group #%d, return the group.', $role->value, $groupId));
                 $this->userGroup = $group;
diff --git a/app/Support/Request/ChecksLogin.php b/app/Support/Request/ChecksLogin.php
index 73bc0dfe84..ee37498e3b 100644
--- a/app/Support/Request/ChecksLogin.php
+++ b/app/Support/Request/ChecksLogin.php
@@ -45,8 +45,8 @@ trait ChecksLogin
         if (!$check) {
             return false;
         }
-        if (!property_exists($this, 'acceptedRoles')) {
-            Log::debug(sprintf('Request class %s has no acceptedRoles array', static::class));
+        if (0 === count($this->acceptedRoles)) {
+            Log::debug(sprintf('Request class %s has 0 entries in acceptedRoles array', static::class));
 
             return true; // check for false already took place.
         }
diff --git a/app/Support/Request/ConvertsDataTypes.php b/app/Support/Request/ConvertsDataTypes.php
index 9982564930..a2253e48ae 100644
--- a/app/Support/Request/ConvertsDataTypes.php
+++ b/app/Support/Request/ConvertsDataTypes.php
@@ -205,10 +205,9 @@ trait ConvertsDataTypes
         /** @var AccountRepositoryInterface $repository */
         $repository = app(AccountRepositoryInterface::class);
 
-        if (method_exists($this, 'validateUserGroup')) {
-            $userGroup = $this->validateUserGroup($this);
-            $repository->setUserGroup($userGroup);
-        }
+        // blindly assume this method exists.
+        $userGroup = $this->validateUserGroup($this);
+        $repository->setUserGroup($userGroup);
 
         // set administration ID
         // group ID