@Debra300We use Booking.com a lot - until this virus hit, AirBnB provided about 10%-12% of our bookings, Booking.com was around 40%. We are an agency and have many properties listed on all OTAs.
We use Payments by Booking.com - this solves many of the issues you mention - guests have to pay at the time of booking. We also set all dates to non-refundable. Guests get 24 hours from the time of booking in which to cancel free of charge, but after that, it's non-refundable. Sure, it costs a little bit more, but it removes all the fake bookings, the calendar blockers etc and saves a vast amount of time.
All OTAs have pros and cons. AirBnB's cancellation policy is not good for hosts, but they do handle the damage deposit automatically. Booking.com's cancellation policy is good, but they are a real headache with damage deposits.
A couple of weeks ago, Booking.com invited me to a Zoom type conference call with various managers and others to discuss the damage deposits. They are make moves to make it easier for us to take the damage deposits, but seem to be branding it as an option extra service. I expressed my concerns that they would use that as another opportunity to charge extra again.
One day, an OTA will start up that will do everything we want, support the hosts properly and will take the world by storm. The likes of AirBnB and Booking.com have become too big and too complacent .....