Same problem. Just got it tonight but this is the first time I tried in a while.
Just to help out the OP :). If, in Steam settings, this says Steam Beta Update like my picture shows, then you're using the beta, otherwise you are not. But I'm sure the build number is enough for the devs 👍 @rokejulianlockhart

https://github.com/ValveSoftware/steam-for-linux/issues/9116#issuecomment-1401991290
Yeah, I'm not, @noobmagnet. I hadn't been able to locate the button, since I was convinced that it wouldn't be in such a prominent location:
Your system information
Please describe your issue in as much detail as possible:
appears when I attempt to stream
app/1905180/depots/?branch=28.1:Steps for reproducing this issue
Install
app/1905180/depots/?branch=28.1via Windows 11 22H2 (Insider Preview).Attempt to stream it from the aforementioned.
Unfortunately, whether the scope of this issue encompasses other applications is unknown, because, from what I recall, I solely tested OBS Studio. However, others corroborate that it affects more applications. [^2] ^3 ^4
[^2]: ⪅
steamcommunity.com/discussions/forum/1/3543798390537668497