Either I got lucky or things are improving on the timelines recently reported here. For a recent renewal, just over 24 hours for UK Border Force code (pretty typical, I think). Full approval received from CBP just over 11 days after submitting renewal application online. No interview (virtual or physical) required.
Wasn't concerned about it, given the 24 month extension currently in place for renewals, but nice to have it sorted so quickly for the next 5 years.