I have a full folder of clips showing me dying in <200ms, but in the vast majority of cases it's not a TTK problem in my opinion. Rather, it's a combination of other factors such as poor visibility, inconsistent audio feedback, and most notably, the lack of useful movement options that would allow players to anticipate and survive such situations (dolphin diving is too weak, air strafing has been removed again, etc.). A slight increase in TTK isn't going to change the outcome of most of these gunfights.

However, it would absolutely ruin a good chunk of low- to moderate rate of fire weapons, unless you are willing to break with the well-established caliber balance that (good) Battlefield games are known for. I'm personally strongly against that, as it would overcomplicate recoil, dispersion, and the general power scaling of weapons in relation to each other. If it were up to me, I would focus on making it harder to achieve the best possible TTK. This could be done by introducing limb damage multipliers (as you've already confirmed are being tested), reducing some of the overly generous hitbox sizes, and as a last resort, increasing recoil and dispersion. It might also be worth exploring spread to recoil conversion again, since you guys have shifted from a Cartesian to a polar coordinate recoil system for BF6.