It isn't about small or big, it's about cohesion of the changes.

I prefer a big feature to be one big PR rather than a lot of small ones.

We had a dev do a big feature with a ton of small PRs, each one was individually impossible to review because each concern was out of scope for the small PR and "would be fixed in later PRs". Once it all came together as as whole, the big picture was a total horror show and I had to rewrite basically the whole thing.

In order to review those small PRs properly, each time I would have to read and understand all the current code so far from the beginning. Without that, each small PR individually looks OK because you won't remember the other PRs from weeks back that already duplicated what the current small PR does for example.