I watch plenty of female vtubers that collab with males, Ui-mama is the only one that feel like she's a fucktoy for male. I'm being completely serious here. Like, other vtubers have a lot of things going on, but Ui-mamas whole character is centered around this one single trait, which is making males want to fuck her. That's why she has sky high R-18 art rate and people scream rape this rape that at her. She even has a husband, Maimoto, which is a blank-state generic old man, as her regular male collab partner that she flirts with all the time, for her viewers to self insert into. And unlike other non-Hololive female vtubers that collab with various male vtubers in various situations(especially in NijiJP, most mixed gender collabs nowadays feel clean and sterile, like they intentionally make it feel that way to not get shipped together), the only male Ui-mama is willing to collab with(at least in one-on-one collab) is her husband, which is also the self insert for her viewers, and the reason she does this is because she doesn't want her viewers to feel like they're getting cucked by collabing with male vtuber that's not their self-insert. This is a pretty big-brain move and I think there's no way she's doing all this unintentionally.
I think this should be counted as one of the GFE method, and personally, I think it's way superior than the 'no male interaction' that most Holo do.