I just recently started using the android app.
I have registered with my personal google email account
My mobile is a Xiaomi Mi Note 10 Pro 256Gb (MIUI 12.0.3 Global)
Installed the latest version of android from Google Play.
I get the following errors when trying to access:
the email is already registered
you cannot log in at this time, usually this is due to a poor internet connection
My data connection is 4G and 5G wifi
It is impossible for this to happen.
From the application downloaded for Windows 10 (through the official store) I can access without problem and I have shared with my girlfriend a notebook and several notes.