Hi Mia,
The answer is simple: Not all extensions are Joomla 6.0 ready. And won't be in next days.
Solution:
Disable if you don't use it, or revert to Joomla 5.x and wait for offcial update of all used extensions.
Tip for the future:
Before you make upgrade to Joomla 6. Just check on extension developer sites if used by you extension(s) & template has been updated for planned Jx version. It takes a few extra minutes, but fewer silver hairs on the head. Don't trust Joomla Installer Tester in 100%, correct that info manually each time in changelog etc.
BTW
Using Joomla 6.0.0 for production site, not the best idea. Better wait for J6.0.1.