Speaking to IGN Japan, Kamiya said that while Bayonetta 3 is perfectly playable without having experienced the two previous games, he feels that players are doing themselves an injustice by not knowing the full story.
Here’s the translation (thanks, VGC):
I’d like you to play Bayonetta 3 after you’ve played the previous games.
We wrote the storylines for the first and second games in a way that you could enjoy them regardless of which one you started with, and there’s no reason why you won’t be able to follow the story and enjoy it if you start with Bayonetta 3. But I’m convinced that if you’ve played Bayonetta and Bayonetta 2 you’ll find it even more interesting. So I hope you’ll [play them to] prepare yourself for the third game.
If you haven’t played the first and second games, I think you’ll be missing out.
Bayonetta 3 was announced as a Switch exclusive way back in 2017 and only resurfaced in September 2021.