Not receiving texts from one person in a group chat

I recently purchased a new Google Pixel 8a and for some reason I'm not receiving texts from one person in a group chat. But I can text them in a solo chat.

They do not have me blocked and I do not have them blocked. They are also a Tmobile customer.

I've done multiple troubleshooting methods and I still don't get their texts. Calling customer service wasn't useful either.

My RCS chats have the status of "setting up..." and it's said that for over a week now, which could potentially be the problem. I have no option to retry verification.