大量の音が重なる場面で音量がおかしくなる症状の応急処置が載ってた
So i found a fix atleast for me. When i started the game i put all the voume settings to max and if any of you guys did the same try putting it back to default.
The volume drop only happens because it goes back to its starting value. Naturally you need to manually turn your volume up after that but its better than having the volume change all the time.
I tried this out, and while it does NOT fix the issue, it does slightly mitigate it in some situations.

Still, in the more extreme instances where there are a ton of sound effects playing at once, such as unloading a machine gun near point blank on a teleportation anchor it will still be very much noticeable.

Well on 100 i cant even hear the teleportation anchor take the hits or the explossion when destroyed and everything around me gets muted this is not happening for me on default settings.
On default at least for me its the complete opposite when i unload my fastes machine gun point blank on the anchor its louder than everything else.

It seems like the software trys to blanace out the louder sounds and put everything on default while ignoring your ingame vollume settings
so having them on default and turning your volume up on the hardware side of things is atm the only solution till we get a real fix.

ノーマライゼーションが過剰に効きすぎてるからゲーム側の音量はできるだけ小さめにしてPC側ででかくしろってさ
有効かは分からんけど、試した人によれば多少改善されるそうな