Would you not then encounter the same problem but upside down, a kind of Australian conundrum
In that you would have to devise a way of isolating the speakers from the ceiling, which is probably more resonant than the floor.
Now suspending a mic from the ceiling could encounter the same problem of the ceiling acting like a large sound board and transmitting that down the mic pole!
Having said that, my vocal booth has a ceiling mounted mic placment on a pole that’s decoupled from the ceiling using neoprene and I must say works fine.