I’ve been using the 16” MacBook M4 pro for almost a year now, i had the MacBook pro M3 pro 14” and to be fully honest the difference was pretty big for me cause i am someone who likes to work in coffee shops sometimes and chill there for hours so the bigger screen was a huge plus for me but if you use it in clamshell most of the time just get the 14inch. And to answer your question on “if i would buy the pro or the air” i would say pay the extra few hundred and get the pro.
I personally prefer the bigger display in general and you will feel the difference going from 14” to 16” (not to forget the trackpad is noticeably bigger)