When possible, yeah. I imagine some sort of golden rule: "make PRs for others to review that you would like to review yourself." There's plenty of room for exceptions there - my coworker is currently reviewing a 1300-line PR after my apologies for it :)

But yes, we generally break things down into the smallest meaningful chunk possible to deliver. If that chunk is too small to understand the larger work that it's part of (as is usually the case for non-trivial work), we can discuss the larger work in another forum (ad-hoc verbally, via design doc, via meeting, etc).