RCS Messaging option not showing up in Settings

Who’s your carrier and what country are you in?

Same, on a 16e with the most recent update.

Situation: I was on Google Fi with a Pixel 8a and had been using RCS. After porting my number to a new provider and switching to iPhone 16e I was missing messages. I worked out that any of my friends who had me in group chats with RCS were not able to text me inside those groups. Individual text messages use SMS and work normally.

I'm on us-mobile, which apparently has spotty support for RCS on iPhone (total support on Android) depending on which network you use. But I don't understand why the carrier has a role in RCS at all, I thought it was strictly a device issue with RCS using ordinary TCP over the Internet. My evidence for this is my Pixel 8a was still getting the missing RCS messages even without any cellular connection or attached phone number. It only needed wifi to receive them. I turned off RCS service on my Android to try to fix the issue but no luck. I've heard rumors that this will maybe resolve in "up to" 8 days once the RCS attachment/association(?) expires and other devices will revert to sms to contact me, but no luck yet after 5 days.

I would love a solution that forced my friends group chats to simply use sms. My friends and I tried deleting those groups and recreating them on all involved devices but I'm still missing messages.

I'm trying to work this out with my carrier as well as posting here, but its not clear to me why Android RCS works without any carrier over the Internet while iPhone RCS depends on the carrier network. That would seem to be a fix for the problem generally, or at least would greatly mitigate the pain of missing messages.

Exactly 5 seconds after I posted this my phone notified me of a pending update and of course that fixed it. Option now appears, I enabled it and got 40 RCS messages all at once. So nevermind, seems to be all set :)