We have shot the savage striker pistols with the adjustable brake ( if you call on or off adjustable
) on them and it really didn't make a difference in accuracy for a given load. It was a bit easier to shoot well though with the brake on I suppose. I'd look at a good recoil pad first and if that isn't enough send her in for a brake.
I'm not much for brakes, and only have one of the 11 rifles I own braked.... mostly because it came that way. That said, if you think you need less felt recoil, you probably do.
As to powder temp. sensitivity, that is much to do about nothing if you've shot the rifle and know your drops in the conditions you will hunt in. I shoot more rl than any other brand and I live in North Dakota. I wish there were a magic potion that made everything the same no matter the temp., but even if you can get your speeds the same at all temps., your air density, barrel harmonics, teeth chattering, and a number of other things will be different.