Rated 5 out of 5 stars

Vasilis Ant's procedure is the fix, along with turning off Provider for Google Calendar. So it looks like Thunderbird now supports Gcal natively, and this plugin no longer works / is not needed.

But it was needed for a long time. Thank you Philipp for bridging this gap for as long as you did!

Google support is useless as usual. I panicked when I could not longer access my calendar and got on support chat for Google Workspace. I ended up finding the problem on this page myself and telling the support person about it. They could only say that they don't comment on non-google products!

This review is for a previous version of the add-on (91.0.4).