Only some channels at high peak times have shuttering video on YouTube TV. The audio is fine, but the video is constantly shuttering, it’s only with some channels. My roku is hardwired into the internet.
I have the same issue - I have a new Sony OLED, new AVR, new HDMI cables and a ROKU Ultra 4660. a user on another thread noted that with older Rokus, mine is a 4660 which is not that old, you need force video/display settings on the Roku to be 4k60hz, and not to use 4k HDR 60hz or Auto. Impression is this is a Roku issue. YouTube TV now works fine.....not sure how that might affect any Roku HDR content.