TOTK has more creative combat, such as my kid fusing a bomb barrel to a shield, which blows up enemies when they attack. Other than that, the combat feels very similar to BOTW, and there's new enemy types (and I think more variety?).

It's certainly gimmicky, and I think the puzzles are easier, though neither has particularly great puzzles. I personally think TOTK is the better sandbox game, while BOTW is a little better Zelda game, but they're both kinda crappy Zelda games IMO.