The timing corresponds exactly to this deployment:

18:04 urbanecm@deploy1001: Synchronized private/PrivateSettings.php: Update T250887 mitigations (duration: 00m 56s)

This doubled the amount of time it takes for edits to be saved.

@Urbanecm I would advise reverting that change. This will confirm that it was the source of the regression. And the revert will give us time to find a performance-friendly way to solve this problem without a continued regression in the meantime.