@Χριστιανα0 One thing you can do before accepting a booking is to not only look at the guest's reviews, but click on the profile of the hosts that left those reviews. Then scroll down the host's reviews to find the review the guest left for his past hosts.
If you see that the guest has left bad reviews for other hosts, when all the other reviews for that host are good, that tells you a lot about the guest and you then know to decline a booking from them.
And as Helen says, flag the accounts of guests who try to book off-platform. If you can get all the other hosts you know to do that, too, these types of people will have their accounts closed. Airbnb really caters to guests in most regards, but trying to avoid paying Airbnb fees by booking off-platform is something they do crack down on.