Most often than not, they are actually self-inserts of the authors lol.
A good fujoshi character I can recall is the girl from Cherry Magic. She's not disruptive in any way and doesn't take up too many space in the story. Plus, she actually helped the MC. She's an ally through and through .
Tojo Sakana is honestly kinda creepy in general, same with a lot of bl authors
ooh ive been considering reading cherry magic since the anime is coming out rn, you've solidified my decision to do so!!
honestly really tired of the trope of having weird fujoshis in otherwise completely fine bl. even worse when they're like someone's sister, like that one tojo sakana manga, cuz that creep ruined my fluffy reading experience. this one is questionable rn but she hasn't done anything egregious so im hoping it stays that way, but it wouldn't be surprising if she got worse lol. it sucks cause instead of writing female characters that are actually allies, mangaka seem to more often than not choose to write characters that treat the gay couple like a fictional ship and "fangirl" over them in a very invasive and uncomfortable way :/