Can I block the time between reservations for resource refuel/cleaning etc.?

Yes. In the resource settings, set the Block time between reservations checkbox and specify the duration.

Yes, you can set the duration of time blocking in the resource settings.

Let's imagine that you set this duration to 1 hour. In this case, each booking visible on the customer's calendar will start 1 hour earlier and end 1 hour later. This will prevent the customer from booking the resource at the time of the intended preparation (refuel, cleaning etc.). This guarantees a 1-hour interval between bookings.