@Norman-G-0 The Airbnb wording for the prep time setting is highly confusing.
One day prep time does exactly what you want. It blocks one night between bookings, so you don't get a check-out and check-in on the same day. It doesn't block two nights, as it suggests.
The "day after" doubles up as "the day before".
Guest A checks out on the 1st. No one can book the night of the 1st. That's the "day after".
Guest B books to check in on the 2nd. The 1st is also the "day before".