I am using weekly 21.5.12. On the previous build I had the same problem.
I'm using google messages - I am trying to send a mms message - it keeps on saying the network isn't ready, try again.
I tried on stock messages - it says I can't attach that attachment... doesn't matter which...
Since Android 11 - votle has not worked with my carrier Telstra in Australia.
Previously on Android 10 - it worked perfectly using the volte USSD codes.
I have flashed all 12.2.x.0 firmwares and tried latest xiaomi.eu both stable and weekly no dice on Android 11.
Does modem test tools work on...