I’ve tried this with 9.2.5 and the RC release, on both the Odroid C4 and N2. It only fails with a single 4K TV (LG and Samsung TVs work fine.)
I have a Vero 4K, and it works fine with the TCL TV.
I get random 2-3 second pauses (where the screen blanks), every 5-10 minutes.
If this is not a known problem, I’m happy to create and submit some bug reports.