My experience is very similar. I'm a lesbian and always felt Stonewall supported and represented me. When they added the T onto LGB I was all for it. Why wouldn't I want to be a good ally to another minority group?
I truly didn't see an issue in recognising trans women as women. The trans women I knew were committed to fully transitioning and I couldn't see what threats they would pose.
Then trans activists started terrorising women in my town, bullying and threatening them out of their jobs. (charity bosses, cafe owners, we all know what happened to Kathleen Stock)
Every lesbian group I was in was overtaken by trans activists. Diva magazine started publishing articles written by an AGP male 'lesbian' who wrote of feeling aroused wearing his older sister's used knickers.
Trans women started winning in female sports, claiming women's prizes, lesbians were transphobic for not taking trans women as partners. Stonewall abandoned lesbians.
The final straw was discovering all the women's refuges and centres in my area has been captured and overtaken by TRAs.
And here I am. Gender Critical.