What to do if your playing with a teammate you met in the game and potentially think they might be cheating but aren't completely sure or have no evidence?

Hi, I didn't know where else to ask about this (topic selection wise) and also wanted it on public record that if this teammate I was playing with is cheating I didn't know, at least not for sure. According to your guidelines you shouldn't report someone unless you know for sure they are cheating: https://help.marathonthegame.com/hc/en-us/articles/47024359626644-Report-Suspected-Cheating-and-Poor-Behavior and was the first place I looked at for this info. I was hoping I could semi-report them and they would be investigated, but, it doesn't sound like that's how it would work and I don't want to report them for no reason (I don't have anything concrete to suggest they are actually cheating).

I met a player in the Cryo Archive map. Since then I've been playing with them and one other player I met on the same match. It's been 2 weeks since then, but, now I've grown suspicious of certain behaviour after looking back through clips of matches I've had with them. They basically have the Cryo Archive map ingrained into their brain (not a problem, I am 99% sure they just know the map real well) which makes it harder to distinguish if their behaviour is from map knowledge or not (especially cause I still find the map to be a maze being newer to it than them). They "hear things" better than me, have more eliminations than me all the time, win lots of fights even in bad situations alone (out my sight) and I've looked at their steam profile and it says they have 1 ban on record YEARS AND YEARS ago which is what made me particular suspicious even though that was ages ago.

I don't want to stop playing with them (our team gets along), I don't have actual evidence against them, but, in case they are cheating I wanted to state this here in case I was just too naïve and got banned with them should they actually be cheating. How does that work by the way? Other than prove that I really didn't know in this post, but, had some suspicions I can't prove (I have no evidence of them cheating) I don't know what to do here.

The obvious answer would be to stop playing with them and maybe even report them, but, if they aren't cheating I just cut myself off from playing with a great player who needs decent teammates (I'm not amazing but I'm guessing I'm one of the better randoms they found, so they play with me, same goes for the other teammate, which by the way I have no suspicions of just to clear their name too).

Anyway, I'd like advice on what to do here. Let's say they are cheating and I just couldn't find any evidence in the future other than a feeling they might be. If they got banned, I assume if I play with them long enough you guys would assume I was "in the know" and ban me/their teammates too? In that situation I would hope I can use this post to appeal.

Please advise me what to do. Am I safe to play with this person? I'm hoping they are just a great player, but, now I'm suspecting they are a little "too great".

Should they do any obvious suspicious behaviour Ill record it and report it right away by the way!