PHP Fatal error: Declaration of class@anonymous::isEnvironmentInFrontendMode() must be compatible with TYPO3\CMS\Extbase\Service\EnvironmentService::isEnvironmentInFrontendMode(): bool in /bigdisk/typo3/vhosts/fotoquelle/packages/warmup/Classes/FrontendRequestBuilder.php on line 55

Fixing this with:
$environmentService = new class extends EnvironmentService { public function isEnvironmentInFrontendMode() : bool { return true; } public function isEnvironmentInBackendMode() : bool { return false; } public function isEnvironmentInCliMode() : bool { return false; } };

the next error is:

Uncaught TYPO3 Exception Too few arguments to function TYPO3\CMS\Extbase\SignalSlot\Dispatcher::__construct(), 0 passed in /bigdisk/typo3/vhosts/fotoquelle/packages/warmup/Classes/FrontendRequestBuilder.php on line 70 and exactly 2 expected
thrown in file /bigdisk/typo3/vhosts/fotoquelle/web/typo3/sysext/extbase/Classes/SignalSlot/Dispatcher.php
in line 296