ShadowBan MW3?

Throughout my time playing the Cod series, I have been shadowbanned countless times. Sometimes while closet cheating and sometimes while playing on a account legit. I have never actually been perm banned but I have received quite a few shadows. Is there a real definite answer to what triggers them?
So far I've heard of the following:

1. High kill games
2. Mass Reporting
3. Switching from console to PC using the same Activision account

I'm just trying to avoid these bans as much as possible.

truthfully nobody knows but what has been the most consistent thing since warzone1/mw2019 are:

1. reports
2. activision account age relating to kill cap
3. a shadowban loop

nothing else has been consistent but nobody knows for sure except activision

game is dogshit needs overwatch style of system

Not even just that, aimbot could also get you SB well more or so headshots. Getting to much headshots will give you SB. I was playing war with a marksman rifle (1 taps headshots), looked legit asf, but I got like 180 headshot kills in that one game and got SB right after