You have to make allowances for the fact that many people are working from home (where maybe it's harder to test code and you certainly can't do hallway usability testing). Things also improved somewhat with the October patch. But Android 11 was a Windows ME level disaster. Google says that they dropped the desserts to make Android 'more accessible to a global audience' but I think it's probably because they know that new updates are no longer sweet.
Multi-tasking is completely broken. In pandemic mode I'm on video calls all day, and dodging the 2-3 video calls that are usually going on elsewhere in my house. Being able to have Teams and notes running at the same time is pretty important right now and with 11 it's not possible.
Other than conference calls and Kindle the other main use I have for my phone is podcasts. Android 11 improved the media controls by moving them to the quick settings area of the notification shade, providing easy switching between playback devices and allowing you to swipe through recent playback apps. All good, except that none of it works. The controls are there but do nothing so I have to run the app to pause. Also, there is a weird ghost of a previous media playback that shows up and then disappears when pulling down the notification shade. And as for dismissing previous sessions that seems to require a reboot.
Multi-tasking and media were fixed in the most recent patch, but there is also some new notification system to separate out conversations. In practice this seems to mean I get multiple groups of Gmail and Teams notifications instead of a single cluster per app. This isn't what I want, gives me more work to do and so far I haven't found a way to turn it off. Notifications have steadily improved over the last few major Android releases so it's upsetting to see them becoming worse.
This is all on a Pixel 4XL which you would assume would get some level of testing love. It used to be that the main advantage of a Pixel was getting new versions of Android quickly. With 11 I'm for the first time wishing I was waiting a few months while the kinks were worked out.