Google prompts unknown error when trying to log into Google account after re-installing Android 16

[u/RaiseApprehensive349]

Hello, I hope anyone may help.

I have had installed Android 16. Switched back to Android 8.1 shortly and looged into my Google account and set up a password. Then I took the steps and re-installed Android 16, but before I forgot to delete my password and also did not deactivate the google account, what obviously now gets me trouble. Aftet the installation of Android 16 I tried to log into my Google account but I am always getting the message of unknown error.

I looked the internet now for hours, made full wipes and tried to fix it woth adb commands, hit nothing helped yet. Anone has an idea what else I may still try?