this makes sooo much sense. Like his persoality ingame vs in rl is so diff at first but then in the current chapter I noticed that he does resemble his character on the game but with a bit of awkwardness or mean-ish vibe..? Then you said about him having social anxiety and it just clicked. No wonder he jumped the first time they met and his attitude towards the mc. Might be because of people who'll go to his cafe just so they can talk to him or something.
I think he's an ISTP... ISTPs always look like the quiet brooding type but they text rlly cute and animated lol. Or at least the ones I know.
I don't think it's because of doxxing or potentially had a stalker (well at least no the only reason) it's ver noticeable that he has social anxiety like when they met in the Cafe for the first time and completely said the sentence out of the order then got overwhelmingly flustered, like it's very easy to see that he struggles with socializing and if he was actually stalked then it probably made worse