The feature One Home Screen will give you the same apps and arrangement. I don't know if it carries over other settings, but it won't transfer your passwords. Enable it on your first Apple TV before setting up the second one.
https://support.apple.com/guide/tv/customize-the-home-screen-atvbad14dc6a/tvos
Sure, but OP is pointing out that not all HDR is created equal. LED screens without full-array local dimming of the backlight might not do HDR that is really any better than SDR, even if it is brighter. It's worth trying some content with and without HDR matching enabled.
Regardless of what any text about the standing says, you only need to have your watch pointed down for one minute to get the stand credited. That can be standing, or sitting with your wrist dangling. I do the latter when I've stood during that hour but while carrying things.