I believe you could just add this into the block list: accounts.google.com/gsi/client

i have 3rd party frames blocked by default in ublock, as well as scripts from google. i assumed that blocks them? i did not actually check though and of course i need to turn the 3rd party frame blocking off when i want to see certain things (but really not as often as one might think) ;w;

There is a custom filter you can copy and paste into uBlock. I searched uBlock stop Google login on DDG a few years ago and found it, and it worked.

How about UMatrix you can blacklist googles urls

Iirc, there was a question about it on Stack Overflow where someone replied with an Ublock Origin filter. Can't check now but if no one finds until I can check again, saving the thread to check myself. But could work? Dunno how to check if Ublock's filters help stop a given element receive personal information.

Noscript is your friend.

Whitelist the scripts you do need, leave everything else (including all of Google if you want) blocked.

Never use an third party account to log in in a service.

With the Portmaster you can block Big Tech completly (Google, Facebook, Amazon, etc), with it these companies not longer exist for you, but the price is that you can't not longer access to any of their services.