You don't need to know anything. There's some cool throw backs, but the story is new with no real link to the previous games aside from some returning characters.

Heck, even the second game didn't rely on knowing the first game's story even though you're meant to be the same character there.

Whether you'd like it based on liking Skyrim or Diablo... Well, it's not similar to those at all other than being RPGs. BG3 is more like old traditional RPGs with actual depth, and a turn-based tactical combat system similar to the modern X-Com games but with more depth from synergizing mechanics (like setting flammable things on fire, turning water to ice, using water to douse flames, throwing tables and chairs, etc).