308's are pretty easy to load for.
I would start with Varget or H4895 and consult online loading are hard-copy reloading manuals for the appropriate bullet weight(s).
I have three 308 Winchester rigs.
Two of them are specialty pistols and one is a F-TR rifle.
I use Varget with the 200.20X 200...
Do you have a 20 MOA sloped picatinny rail or rings that can achieve the same?
If so, you would add 20 MOA to your 31 MOA.
Having 50 MOA of internal adjustment lets you go a long way.
If, you have a good reticle, you can go even further.
7mm Dakota (Little less than a 28 Nos) with 180's @ 2886.
Velocity is slower (Shorter Barrel) but the powder charge is close to a Nosler.
Holland Brake again.
Hard to say, but a good solid bottomed brake should reduce 50-60%.
Even that is a perception.
A brake does a much better job than a suppressor.
The more gas you have, the better the brake should work, as you have more gas to let the brake work.
You may want to experiment with a mandrel to expand.
Use a Wilson type seat die with a arbor press.
Main thing is what it is doing on the target consistently
On deer sized game, I don't think it matters, even going up in size, the 165 being bonded will handle it, and the 180 BT should work as well...Shooter's Choice!
I use Salmon River myself, and I like light trigger and quality muzzle brakes.
Borden clone Alpine XP-100 action, 25-284 (7.5T) Bartlein Carbon barrel, Dell trigger (Under a pound), Holland Radial baffle brake, and a shortened SRS rail.
The 28 will definitely have a shorter throat life than the other cartridges you mentioned, but everything has it positives and negatives.
A shorter barrel life is not a problem on a hunting rifle in my opinion.
How many rounds a year would you likely shoot it, once your initial load development...
I have a complete custom 28 Nosler (Left-Hand Action-Not Nosler) with a 8.5T (Brux), and a muzzle brake, with a Manners stock that has never been fired yet. Think it has a Jewell trigger
I won't be taking anyone's place...
Nice Rig!
I like Triple Nickel, I just have not used it that much yet.
Again, Welcome!
I don't use the AR platform much, and I tend to use shorty barrels (single-shots the majority of the time).