Hello, after migrating to Joomla 4, the theme works on frontend (even if something has changed and I’ll have to fix it with css). Unfortunately the theme control panel is no more accessible. After a long wait an error 500 appears: The server returned to "500 - Whoops, looks like something went wrong." .. (ps .. Php 8.0.13) I reinstalled the template (2.0) - also with quickstart - and SP Page builder (3.8.10). What went wrong? What can I do?

Thank you very much

PS After the migration, it seems that "custom.css" is no longer "important" than "template.css". Rules in custom.css that modify those in the template.css are ignored. Do you have suggestions for this? Thanks