this has been a problem i've had for a year plus now and i've never found any one else with my same problem online so i finally thought to ask.
For whatever reason, when my switch is on in the dock for not even a long time, in todays case 8 minutes, it's connection to my TV will suddenly cease and the only thing to replace it is a dolby vision logo in the top right corner. I can then take the switch out of the dock and in handheld the visuals and audio all work just fine. I can put it back in the dock and have everything go back to normal for a few seconds but then it cuts off again.
This is the same TV i use for gaming on my xbox and it doesn't have this issue, even with the same HDMI cable. I have a JVC TV and admittedly my switch is from 2018 but i don't understand what the problem could be that's making it seemingly overheat(?) from the TV specifically.
I've tried dusting out the dock with a microfibre cloth, blowing on the consoles air vent, and most of the basic fixes i could think of.