Because You use Nvidia, I would suggest that You use Xorg instead of Wayland but You have already wrote that it happens there, too.
On the following Link is explained how You can install the Nvidia 550 Driver. Maybe this will cause the Issue:
If that shouldn't work, I honestly don't have more Ideas to that. Exept that You download a new ISO verify the Checksum and create a bootable USB Stick and make a fresh Installation.
Let's add some People here, who have more Experience than me. Maybe they have better Ideas. @Aravisian , @zenzen , @zabadabadoo , @Storm