I learnt a lot of my mixing from my days as a TV producer recording music for jingles or backing tracks for films.

With a professional desk you can compress the vocal signal before it hits the tape (as it was in my day) or the digital recording.

But once you've recorded a compressed signal that's what you've got. You can't uncompress it.

Whether you can compress an incoming signal before it hits the DAW I'm not sure and it will vary from set up to set up.

Some valve/tube preamps automatically compress the signal anyway and I occasionally use one before inputting an analogue signal for recording as opposed to a digital signal vis USB.

As to mic technique and the proximity effect I've found the booklet that came with my SM58 stage mic and it definitely says closeness boosts bass frequencies - and that would be lost if you reduce gain by standing further from the mic.