I read your note a couple of times. What audio/microphone driver is now active?
I didn't do all what you said, I simply forced the 2004 install. All the audio/microphone stuff works as far as I can tell (they're still Conexant). I checked out my stuff on Zoom, and it's happy. As I reported earlier, the only problem I had was when resizing the iTunes window. All other windows resize fine. I'm not too concerned about that. I already posted an item on the Apple-iTunes-Windows community forum.
Update: I don't regularly use iTunes. Perhaps this problem existed before the 2004 update but after the last iTunes update. I really can't say for sure, but I think it's the 2004 update. I checked all my graphics drivers and they are at the latest version.
I didnt force install windows 10 2004. All i did is that i replaced Conexant driver with Microsoft provided generic driver.
After doing that i had to wait 2 days to get offered with the Update by windows update. Then I updated to 2004. Now I'm using 2004 without the conexant drivers. I don't have any issue so far. And I find Microsoft audio driver far too feature rich than that god-forbidden hideous conexant driver.