TTK is inconsistent because they decided to handle lag the same way CoD does, by very aggressively desynching your client with the server in order to never ever "show" lag, like you or others teleporting, people walking in place, hitmarkers being super late and so on.
On your end the game always feels like it's almost local or LAN, hits feel instantanious, but due to this way of handling lag, what is happening on your screen is often very different to what's happening on the server. That's why you frequently shoot first, hit first and then seemingly get hit 5 times in 0,1 seconds and die, or have enemies just walking through a barage of fire taking no damage. Winning or Losing gunfights you most certainly shouldn't have. All this happens with other games too obviously once in a while, but the amount of time it happens in BF6 makes me pretty certain they use a very similar system to CoD.
If you ever actually see the lag, you're so far desynched you might as well be playing a different game.