I review PRs daily, usually 3 or 4 but sometimes more. They either get approved and merged/deployed immediately or sent back for re-work. No stale PRs: a pull request should be ready to merge.
I strongly encourage the programmers to submit small PRs so they are building incrementally rather than changing a lot of files at once. That keeps reviewing and testing easy.
None of the projects I work on use formal or strict TDD. I think it’s important to have multiple pairs of eyes reviewing the code.