@Joanna522 As far as I'm aware there is no way to do this. Prep time settings are only one or two days between reservations. You could manually block out 5 day periods, only having your calendar availability for half the month, but that would lose you bookings if guests wanted blocked dates.
As far as bedding and towels go, the virus is said not to survive on porous items like cloth for more than 24 hours. So as far as that goes, I don't think you need be too concerned - just handle the bedding with gloves and wear a mask.
But of course, you should do whatever you feel you need to to stay safe and healthy.