Also add a PR reviewer bot. Give it authority to reject the PR, but no authority to merge it. Let the AIs fight until the implementation AI and the reviewer AI come to an agreement. Also limit the number of rounds they're permitted to engage in, to avoid wasting resources. I haven't done this myself, but my naive brain thinks it's probably a good idea.

The problem is most of the people we have spent the last 20 years hiring are bad at code review.

Do you think the leet code, brain teaser show me how smart you are and how much you can memorize is optimized to hire the people who can read code at speed and hold architecture (not code but systems) in their head? How many of your co-workers are set up and use a debugger to step through a change when looking at it?

Most code review was bike shedding before we upped the volume. And from what I have seen it hasn't gotten better.