I went and read that thread. I'm not a member there, plus I haven't used my Sirius app regularly since the 21st. It worked that day, because I play it at work. Those guys were reporting issues on the 17th.
The speculation from that thread is that several apps using 3G may or may not be working right "since the update". Sirius has not issued an app update in quite some time, so that *could* leave the most recent ROM changes as a potential problem. Over my break, I installed MIUI 12.11 first, then 12.24. When I launch the Sirius app under 3G, it does log me in but fails to connect to the last channel, any channel, correctly.
I just did another test. I started the app on Wi-Fi and got it playing "70's on 7". I then switched it to 3G. It played for about 60 seconds on 3G, then the phone went completely dead. Couldn't turn it on from the switch. Pulled the battery and restarted it. After boot, I started the app under 3G. Nothing. Minimized it and turned on Wi-Fi. Not connecting. Shut down the app and restarted it with Wi-Fi and it took off fine. I then repeated shutting down Wi-Fi and let it go to 3G. It has been playing for several minutes and has started a new song. I'm going to leave it on for a bit and see what happens.
Just hoping that what I report may help in diagnosing the problem to someone.