@Lee353 I don't know if you take back-to-back bookings, or leave a day between bookings, but it's something you might consider for the future.
Having that one day prep time, while it means an unbooked night, can work out better in the long run. If you find a guest has broken or damaged something, or through no fault of the guest's, something has gone on the blink, it gives you leeway to get it replaced or repaired, and also to notify upcoming guests if it might not get fixed by the time they arrive.
Messaging a guest to say you have a problem with the hot tub and are trying to get it repaired before their arrival, and if that doesn't happen, you will discount XX % per night that they are without it, is preferable to trying to get it fixed in a rush in the few hours you have between guests, or not being able to reach them because they are in transit, only to have them arrive and find something unusable.
The one night block also relieves the stress of early arrivals or late check-outs or scrambling to get the place cleaned after having dirty, messy guests.
Sorry you got the "You ruined our vacation" types. If all it takes is a briefly unusable hottub to have one's vacation totally ruined, they are going to have a lot of "ruined" vacations in their lives.