I think I would like something along the lines Skyrim’s system, where you just get better at skills by using them, but with more perks that are actually impactful and fewer perks that just boost damage without really changing how you play.
And enemy level scaling should go. I always hated seeing random bandits on the road with top-tier weapons and armor. It breaks immersion and makes my progression feel less meaningful.
I like your idea for level scaling in some places but not others! That would mean the main story and maybe some important side quests can always be appropriately challenging, but random no-name bandits won’t be walking around with enchanted daedric weapons. A perfectly immersive compromise.