How often do you have to review large pull requests?

Hey developers, today I have a simple question. 🥹

How often do you have to review large pull requests? Like 50 or 100+ files PRs? If so, do these PRs often contain changes related to things that aren't related to the initial scope of the issue that the PR is tackling? Or it's all within scope?

Finally, would it help if the PR was split into multiple smaller PRs? So that the code reviewer could digest / merge them in smaller chunks.

Thank you! 🍺