So, here’s the thing.
If you have any PR waiting for a review, your WIP limit is already too high.
If it wasn’t, you wouldn’t have any queue/wait time.
The highest WIP limit you should have is the one you get when pairing.
The lowest one you’ll get with one-piece-flow when mobbing.
Lower WIP reduces lead times and increases throughput.
Not to mention the difference in quality you’ll get.
PRs based workflow is, by definition, decreasing the throughput, increasing lead times, and killing your flow efficiency.
Don’t even get me started on quality (theather) you get because of it.
Show some love to your team’s flow. It will help you relieve the pressure, build the quality in, and sleep better at night.