Questions: Dating

So, I've never rlly been in a relationship and I've been chatting to this guy that I met online for some time already (I've never seen him irl tho!) but then realised that he follows lots of "suspicious" accounts and some might even be OF accounts of women on IG.

I'm not sure if that's a normal guy behaviour or not but it seemed pretty weird to me and now I'm second guessing, so what do you think? Is it a red flag?

Worst is that I don't even know how to bring this up to him.

I see a lot of discussion around height preferences in dating, how they are compared to weight and body count, how they influence a person's overall attractiveness, etc.
So I ask the question:
Should height matter? And is it fair for a person to be turned down for their height?

I ask this question because I have had friends as guys in the past where I had originally thought we were just friends but getting after 3 months those friends start to hit on me and indicate more interest in me which I decline because I only wanted to be friends. They would sooner or later stop talking to me all together.

I like having some male friends as I like to game on the side, I have yet to see another girl gamer but this scenario made me wonder whether guys and girls can stick to being platonic friends, or will it eventually lead to more down the line, or do guys intentionally make girls as friends to move into a romantic relationship?