@Maria2866 There have always been Airbnb service fees for guests. These used to be about 10%, but have gradually increased over the years. Now some places have a 12-25% service fee, but how they determine the percentage charged is anyone's guess. It's not a nightly fee, but a percentage of the total reservation.
But the fees have gradually increased, so I doubt that is why you are suddenly not getting as many bookings. Maybe it's seasonal, maybe there is more competition in your area, maybe your search ranking has dropped due to any one of a myriad of factors, maybe people just aren't travelling as much (the coronavirus scare may be having an impact), and I think a lot of guests are fed up with Airbnb because of their poor customer service. Hosts worldwide have been reporting that their bookings are way down in the last few months, even before the coronavirus. Mine are as well.
And I agree with Linda- your Airbnb offerings are delightful.