Chrome is entirely removing third-party cookies by 2022.
https://www.theverge.com/2020/1/14/21064698/google-third-par...
https://www.theverge.com/2020/1/14/21064698/google-third-par...
This includes things like clearing the cookies leaving Google cookies alone, to sending a header with a browser ID to Google domains. I really doubt Google will get rid of all theirs methods to tie in their scripts on third-party websites to one user ID, as that will greatly reduce the effectiveness of Google Analytics or ReCAPTCHA.
Or just how aggressively google wants you to login to youtube these days.
Maybe Chrome doing it will get them assed to fix it.