i made some research, because you guys have some legit points, and im 80% sure the pics posted in the /pol/ thread are all screenshots from his instagram not posted by him, because all the images are 1080x1080 or lower. BUT the thread, which I have linked before (https://desuarchive.org/r9k/thread/56643689/#56643689) and where all the rumours started, has an opening pic in full quality, which means that it wasn't screenshotted or downloaded from instagram, but either him or a friend (whom he sent this picture through discord) posted it and made the thread.
so there are still possibilities that the guy, who outed him as a baiter and who spread rumours about him and marky, wasn't larping.
he also said that marky's piano playing ex and some sheep members were following him on instagram. can anyone confirm that?