My comment made on the bug report was (shortly before this ask ubuntu question was created) has been confirmed valid
I fear this is the consequence of an announced google chrome/chromium
change, and cannot be corrected (in fact more API functionality is being
removed in the not too distant future) and this is just the start of the
changes announced with
https://developers.google.com/web/updates/2020/12/chrome-88-deps-rems)
Or as Olivier Tilloy (osomon) ; a Ubuntu developer reported
This is an unfortunate consequence of a decision by Google to restrict
access to the sync API to Chrome only (which explains why in comment
#3 you're seeing that chrome 89 on linux works fine).
There's a lengthy discussion with details here:
https://groups.google.com/a/chromium.org/g/chromium-packagers/c/SG6jnsP4pWM/m/Y73W4CecCQAJ.
I am quoting the part that's relevant for end users:
« What does this mean for my users?
Users of products that are incorrectly using these APIs will notice
that they won't be able to log into their Google Accounts in those
products anymore.
For users who accessed Google features (like Chrome Sync) through a
3rd-party Chromium-based browser, their data will continue to be
available in their Google Account, and data that they have stored
locally will continue to be available locally.
As always, users can view and manage their data through Google Chrome,
Chrome OS, and/or on the My Google Activity page, and they can also
download their data from the Google Takeout page, and/or delete it
from this page. »
I'm afraid (and sorry) there's nothing that can be done from a
packaging perspective to mitigate this regression. Reverting the snap
in the stable channel wouldn't help, because it's not a version
problem. The official announcement states that starting March 15
attempts to log in will fail anyway.
I suppose that users that can't do without the profile sync feature
will need to move on to using the official chrome package distributed
by Google, instead of chromium (which is probably what Google wants,
really).
before closing the bug report with "Won't fix" (so Blame Google)