Find N6 RCS Issues

Hi all. I just picked up an N6 yesterday from Facebook marketplace and absolutely love the phone, coming from a Z Fold 7. However, my RCS chats are in a constant loop of sending as RCS but receiving as SMS/MMS.

The only "fix" I've found was that Google Messages needed an update, which helped for a few messages but the issue came right back.

I've also tried:

Installing and installing the app, both as beta and public

Clearing storage and cache

Removing ColorOS's Messages app via Cantu.

Toggling RCS off/on

Ensuring the automatic switching to SMS is off globally and per contact.

Installed Carrier Services via Play store.

If I switch back to my Fold 7, messaging works fine. Any other ideas? I've looked at other posts across Reddit but so far no luck in getting this permanently fixed.