

Honestly, it doesn’t really matter, pick the one you’re most familiar with. Performance-wise, distros are largely the same, unless the distro ships really old libraries or something.
So I recommend either Debian or Arch since that’s what you’re familiar with.
If you want to try something new, consider openSUSE MicroOS. It has a readonly root like Steam Deck, and you interact with it in transactions, so you get a really solid system. Theoretically. I haven’t actually used it, but I do plan to once I need ti reinstall one of my Tumbleweed systems (or maybe I’ll reinstall my Leap NAS at some point).
And yeah, avoid the nvidia open source drivers. It’s a cool project, but performance sucks because nvidia refuses to provide technical documentation.
Eh, I don’t think the energy use difference is all that important. It gets a lot more complicated if you factor in the ink drying out before being fully used, which means we’d need to produce and transport more ink. Also, a lot of the energy use for a laser printer is during warm-up, so if you print in big batches, the energy difference is a bit lower since it’s amortized over the amount of pages you print.
So just looking at wall power draw only tells part of the picture, and if you’re only using it a few times per year, it’s largely irrelevant (maybe a couple KWh/year difference?).