Sequels in general are almost never as good as the first entry and usually their biggest sin is they are a remake of the first film in some way or form. Or they destroy the goodwill of the first entry, do things that aren’t in the spirit of the original film.

Honestly the Godfather 2 and Empire Strikes Back don’t make those mistakes but a lot of franchises do.

I’ve never seen a third entry i thought was better the the first film in a series ever. And almost never better than the second with few exceptions.

Even the best of the third films in franchises like Return of the Jedi, aren’t that good. Fun and enjoyable if you aren’t looking to be critical and nitpick. But great entries in their own right, stand on their own. Hardly.

Return of the King is an isolated case being better than the Two Towers but not better than Fellowship of the Ring.