I can’t help with mods, but other games scratched the same itch for me. The wild era zelda games (breath of the wild & tears of the kingdom) are a dead ringer, and I probably spent over 600 hours across both. The Horizon series (horizon: zero dawn, horizon: forbidden west) are really good. A bit more story than skyrim, less caves, but still lots to do, and if you don’t know the story, the first game has so much mystery in its world building thats fun to discover as you play!

I prefer the fantasy genre, so similar sci fi games didnt do it as much for me, but some of the fallout games and the outer worlds games are similar gameplay. The Outer Worlds 1 is basically just Firefly but with less charming characters, but i mean its hard to compete with Nathan Fillion, Gina Torres, and Alan Tudyk.