There are no complaints about ubuntu 20, because, apart from the proprietary Skype, all open source applications from the simple Audio Recorder to the complex OBS Studio have no problems with microphones. Their work from microphones is visible on the Record tab in Pulse Audio, and only for Skype this tab is empty.

As we can see on the Internet, this Skype problem has been around for many years. It is solved in a particular way each time.
Therefore, we ask the Ubuntu team to ask the Skype team to look in the code of a simple open source Audio Recorder application, how they found an universal solution for all microphones for all cases.
If the Skype team is not interested in this approach, then the suspicion arises why the proprietary software does not want an universal solution to the problem.