That’s what I do, nieces and nephews. They are a bit older than my kids, and their parents are not tech savvy.
I basically have a kids library for anything under PG, and I grab common sense media ratings for a decent estimate on appropriate age, and let them go from there. Then I use tags for what we find appropriate for our kids.
Some of them still use other things I wouldn’t go near (YouTube kids, ffs that place is wild and weird), but that’s their decision not mine.
FWIW I run mine off an 8th gen Intel, igpu for transcoding (though mostly I don’t need to transcoded), on a little lenovo tiny workstation I picked up on the cheap. Storage is on my NAS.
With no server-side transcoding, yeah the nuc is plenty, but I also run my media server (JF containers, to be specific) on Debian.
If you do end up needing transcoding, the newer Intel stuff is great. I’m considering arc actually for other reasons, but ideally anything skylake (for HEVC) or Kaby Lake (hevc 10 bit) on up is a rock solid choice, no external GPU needed.