I don’t know if this is even possible with the current Channels implementation of PIP on Apple TV, but I’ve seen other tvOS apps do this so maybe it could be implemented.
Currently PIP shows on the screen and then moves around to “get out of the way” when you’re navigating the guide. Would rather just love to have it in a permanent location. For example, I think the upper-right hand corner would be perfect. There is room above the guide, just might need to wrap the show title and description if they get too long.
I know some other channel viewing apps put it in that location and it seems to work well. Just not entirely sure how they’re implementing it.