It seems that this issue is still unresolved. I just installed UT 24.04 on a Tab M10 HD and I'm having the same problem. I've tried adjusting the timeout, but the screen stays on most of the time unless I hit the power button. Any updates on this?

I'm a newb trying to find a decent phone that will work with UT here in the US. OTA-9 has been released since the Eric Heintzmann post. Any updates on devices that currently support VoLTE for T-Mobile? The OnePlus 6T was listed as a device that received updates, but no details on what exactly. I also noticed its listed as a non-maintained device on UT's site. I've searched extensively online, but keep getting conflicting information. So I guess here are my questions:

1. Can anyone confirm whether the OnePlus 6T with UT has VoLTE support and will work on the T Mobile Network?

2. If not, can anyone recommend a device that does besides Xiaomi, Volla, Fairphone, Brax?

From what I've read the POCO X3 will work in the US, but it doesn't have all the bands, so service could be hit or miss. Like the OP, I'm just trying to find something that will reliably work for the basics (calls/texts) here in the US. Sorry for the long post.