Just started work on a project. Greenfield and "AI accelerated". PRs diffs are in the range of 10s of thousands of lines. In the PR, it is suggested to not actually read all the code as it would take too long.
If you push a change, or you approve, you're responsible for the change and its effects later. Regardless of size. If change is too big, tell your teammates its too big to review and to refactor to bite-size with their great coding agents. Use AI models also for review of large changes, consider a checklist . Setup CI and integration tests (also can be AI assisted)