Uncaught ErrorException: Return type of Illuminate\\Support\\Collection::offsetExists

[trogers1884]

After upgrading my Laravel 8 app to Laravel 10 I get the following errors:

PHP Fatal error During inheritance of ArrayAccess: Uncaught ErrorException: Return type of Illuminate\Support\Collection::offsetExists($key) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, ..../vendor/laravel/framework/src/Illuminate/Collections/Collection.php on line 11
and
PHP Fatal error: Class "Illuminate\Support\Collection" not found in .../vendor/laravel/framework/src/Illuminate/Collections/helpers.php:15 .....

All references to these errors that I can find are for older versions of Laravel and the discussions indicate its a PHP incompatibility. I have tried PHP 8.1 and 8.3 but am still getting these errors with either.

Updates were done for software upgrade compliance requirements since Laravel 8 is EOL.

Thanks in advance for any help.