If you turn off RCS a day or two before switching and ensure you message these groups after this is typically negated (at least in my experience) GrapheneOS just put out a way to use RCS on its OS this month which is really nice, I have it on its own profile for RCS and use open bubbles for iMessage/FaceTime and I'm astounded how well it works tbh. But the goal is to slowly harass enough of my frequent contacts to get on signal, so far I'm doing great, my largest hold out being my wife lol

I had this issue on Fossify messaging. When I used native messaging app the problem stopped. Also, it helps if you name the text group. Like I said though, no issues here except with Fossify, and the same thing happened in my Samsung phone so it wasn't Eos that was the issue.

...or rooting the phone, but google comes up with new bs every month to keep you on your toes. the only solution is to force the friend group to get another app.

personly i used rcs for a week, and got like 5 spam messages, so i deleted the google sms app and been using fossify since.