My preference in Old School 1911 finishing was:
2 Tone; HC Frame, Blued Slide.
Or
All Hard Chrome.

Bead Blast Frame and Slide, but Brushed Slide Flats looked “Proper” to my eye.

I made certain to see if any changes were needed, before sending for finishing.
At that time most ‘Smiths wouldn’t do machining on guns that had been HC’d or Melonite finished.

I used Bob Cogan at AP&W most frequently for HC, Bluing and they did Ceracoat as well.
For a Competition/Range Gun HC is hard to beat for Abrasion and moderate Corrosion resistance, although it will rust.

Actual Black Nitride/“Melonite” (not Ionbond, DLC) is about Bullet Proof (think Glok slide) in both those regards.
H&M Black Nitride in Akron Ohio are Masters at this finish.
There are few actual Black Nitride/Melonite finishers. It’s common to hear “blah/blah is just as good as…..holds up as well…” etc.
It isn’t, it doesn’t.

There most certainly must be additional options that I’m unaware of.