For me, changes are as small as possible, however it depends what I'm working on. Currently I'm doing major refactors to get a 1.5 MLOC monolith codebase onto a new runtime. This involves significant refactoring. You don't want to change many things at once, so one refactoring for example might be to make a commit which removes a pattern that will no longer exist in the new runtime. That can easily be 2000 files changed for a total of 10,000 lines. The commit is atomic and does one thing and would not make sense to split up.
With that said, even though it's the same atomic change in each file, the reviewer would still need to check them all.
With that said, even though it's the same atomic change in each file, the reviewer would still need to check them all.