I have lots of criticisms of BF6 but the acid tripping gas is not one of them.
I actually like it. I usually dont put on a mask and just deal with it. Although I dont find the mask limits ADS and movement. If you remember back in BF1 the gas mask would prevent ADS and it was horrible. I actually think this does a decent job of simulating what high stress environments are like in actual combat where you mind starts misinterpreting environmental factors.
I also think its much better implemented than the freezing/cold mechanism was during the winter Manhattan bridge limited event.
The snow/freezing was chopping and really hurt gameplay, probably due to bad and unoptimized code.
This gas mechanic however works pretty seamlessly without any noticeable hit to performance.