Pretty similar to you, but a lot of my groups faced disbandments / hiatus's or forever hiatus's and constant members leaving (like the original line up for 24K for example). BLACK6IX. BAP. 1TEAM. Wanna One.
Nine Percent. (Chinese Group that had a short contract). D Crunch. TRCNG.
For the other three groups I was a fan of 2017 - 2019, then all the sudden all of these groups just got so popular and the fandom is no longer what they were. They are unfortunately now known for their toxicity, and I wish we could go back, 2017 - 2018 was the perfect time in those fan bases. But it just got overwhelming to me. And a lot of fans said I was a bad fan for focusing and helping Nine Percent.
I had a fanbase 'union' account for them, and during the show I reminded people to vote for their picks, and to write letters to them. As the letters often got read as they were translated to Chinese for the members by the staff. And stuff.
Not to mention how OmegaX, TRCNG or BAP was treated. That just made me uneasy about a lot of things.