I had a similar experience. I was in an online authors' group with about a hundred people who'd never met in person. One author (she is cisgender) wrote a nonfiction book about gender, so I bought and read it, and there was a whole chapter about trans people that I thought she'd handled well (she'd interviewed a dozen, maybe two dozen trans people for the book), so I wrote to her publicly, complimenting her and introducing myself, saying I also had a book. I never heard back. (That's fine.) I gave her positive online book reviews and made promo articles for the group that included links to her. Gradually I became aware that she was accepting love-bombing from the "gender-critical" crowd. When her book went from hardcover to paperback, she blogged about her regret for having amplified the voice of trans people, saying she shouldn't have let them speak for themselves about their own genders. I think her paperback edition has a revised introduction where she adds transphobic caveats to her own previous work, but I wasn't going to pay for a second copy of the book to run that comparison. She is very, very far down the anti-trans rabbit hole by now, prominently podcasting away, accepting praise from the loudest celebrity haters while pretending not to know who they are, and retweeting disinfo from within the "GC" vortex. I stressed about it for a long while. Finally, I scrubbed the positive online book reviews I'd given her (except for one that isn't deletable), deleted her from the group promo article I'd blogged, and removed her book from the retweet queue. Then I wasn't stressed anymore. I didn't inform her I was dropping her because I don't owe her that. She's never said hello to me, nor thanked me for promoting her to begin with, and I've never owed her anything—even if I had once owed her something, I wouldn't owe her anything anymore. We walk alongside people for a time, they may discover or reveal their true agendas slowly, and we don't have to keep pace with them. It's OK to part ways.