Since Ubuntu's 20.04 official release, I've seen more and more questions related to microphone not being detected, white noise, headsets with only speakers working and etc, especially in the first few months of the release.
Most of the questions remain unanswered, and even new questions that pop every day remain unanswered.
I can't assess the actual amount of such questions as not all are correctly tagged, but when querying the microphone tag with the 20.04 search string, we may find around 130 matching questions and only few are answered, let alone accepted.
It is also to be noted that the 2 most answered questions (Q1 , Q2 ) contain many different possible solutions and comments, which differ greatly one from another. It seems like there are no common known solutions you can mark questions as duplicate or suggest in the comments with them.
It also seems that there was a known bug when upgrading the system to 20.04 after its release (Q3), but I'm sure that's not the cause for all or even most of the questions since then.
I personally did not encounter such problems, but is there an actual list of common problems with verified common solutions that may help answering such questions?