My Roku Ultra 2019 is connected through my AV Receiver [Onkyo tx646] through to a Samsung Q80 4K tv. The ultra is also hard wired with ethernet.
Occasionally the Roku will crash and restart itself. And at times will drop out sound for a second or 2.
We primarily use Hulu live and YouTube casted from a tablet to the Roku.
I have taken the Resolution from auto to the 4k 60fps setting, as we were having issues with "unsupported resolution" appearing on the AVR. When the restart or crash happens, the resolution setting is reset to auto each time.