Dylabeatus,
I think your question is asking “which muzzle device will increase the functional life of the blast chamber baffle”.
From my experience and conversations with others with experience a muzzle brake will reduce some visible blast chamber erosion compared to using a flash hider or direct threading. Having said that, muzzle device type makes no functional difference. A user will go through many barrels before shooting out a suppressor core when staying within the shooting schedule it was designed to withstand.
For Example:
If one takes a titanium suppressor and does a 100mag dump in 3min, using a muzzle brake over a flash hider will not save the suppressor. Similarly if hunting deer with a titanium can, the use of a muzzle brake is not going to matter as the suppressor will already outlive anyone alive today already.
The second question (and Agelewei’s question) about audible volume may be impossible to adequately answer. Sound performance is dependent on many factors, blast chamber volume, baffle spacing, number of baffles, baffle shape, internal volume, and even cartridge. Larger blast chambers in some cases are associated with more first round pop, closer spaced baffles tend to work better with lower pressure cartridges, but higher pressure cartridges tend to like fewer more spaced baffles. Many manufacturers offer two models of the “same suppressor” one in direct thread and one with a muzzle device mount. The only issue is they are not actually the same suppressor. The mount version may have less baffles or a purposely longer blast chamber to accommodate the mount. It’s never an apple to apple comparison for sound performance between mount options as the actual blast chamber volumes (minus mount space) and number baffles are not controlled. Again this ends up being to a degree cartridge specific as to which will sound best.
When picking a suppressor mount it may be helpful to consider the choice based on function:
Is the suppressor going to present on the rifle at all times? Direct Thread
When using the rifle without a suppressor do I want more flash reduction? Flash Hider
When using the rifle without a suppressor do I want less recoil or muzzle movement? Muzzle Brake
As for Shoobe01’s note on the YHM, this is also the case for a few other suppressors. The DeadAir Wolfman will take higher pressure cartridges when specifically mounted with a KeyMod brake vs direct thread as well. I don’t have a Wolfman on hand yet to test why this is- does it have to do with mount strength, blast chamber weld strength, or baffle core strength? I would caution on using this as means to say a muzzle brake is protective of the baffle core. It could just as easily mean in these particular cans using the brake mount reduces the chances of launching the suppressor off the rifle vs direct thread (or blowing a weld).
Hope this helps. Suppressors are a very deep and addicting rabbit hole.