After rebooting my phone (android 12) all widgets became invisible or started showing "loading"/"widget unavailable" messages. Does anyone know how to solve this?

I prefer to keep it as plan Z since there would be many password recoveries and backups (and hope that I can also backup settings) to do. If I haven't solved it in a couple of days, I'll try that.

Edit: I tried to uninstall an app that needed no backup, but the widget is still invisible. Also, some system apps' widgets don't work either and I can't uninstall those.