Someone in the thread mentioned that he got into Touhou through gacha, and I think it checks out. He has some reposts of Touhou LW on his old Twitter account, additionally he claimed to be a touhou fan here. All of this happened in November 2020, about six months after Touhou Lost Word's release.
I don't doubt that he (probably) played other Touhou games before that, but Lost Word seems to be his main interest and main source of Touhou knowledge, along with fangames and other easily digestible content. After all, the original games are too hard. Why waste your time on them, when you can play gacha, goon to girls kissing, or fantasize about you and Sakuya?

He was simping for Hatsune Miku until 2023, but then he switched to Sakuya around the time when Touhou gained more popularity online. After that, he completely retconned his story, claiming that he loved Sakuya since 2014 (along with a very strange excuse about being a Miku fan, what circumstances forced you into loving her so much? Oh, poor little boy, he was forced to shit out tweets about her every day due to circumstances that he won't go into detail about! He was also in a "relationship" with her, screenshot below).

He might not be a grifter, but he certainly is an attention whore, maybe that's what his "circumstance" for basing his previous online personality around vocaloids is? And he knows that. That's why he "doesn't want to go into detail about it". And that is also a reason why he switched to Sakuya, it was the next "big thing" on the Internet that he could latch onto.

Also, even then he was "lgbt-ally" and all that shit, totally not a pathetic attempt to get some attention:
