When I was upgrading from 2019 16" I wanted to try M2 14" but was worried about the speakers as those on my intel 16 were incredible. I would not take portable speakers on the trips anymore, and would just use laptop in the hotel rooms.
So I tested M2 14" for a few days and compared it my 2019 16". I put them side by side and played a few songs, I could not hear a difference in quality. Just great speakers.
At the end I went with 16" M2 just because of the screen size, the speakers were not a factor at all (the 16 M2 are of course even better though).
I would say, if you are thinking about the speakers as a deciding factor, don't. 14 are awesome.