It would be nice if this ad at least explained a little bit of the technical side of the solution.

We’ve got a separate blog post all about how traffic control works: https://planetscale.com/blog/behind-the-scenes-how-traffic-c...

It sounds vaguely like InnoDB’s concurrency control solution which uses tokens [0] as a unit of maximum work a query can perform.

0: https://dev.mysql.com/doc/refman/8.4/en/innodb-performance-t...