Except that the video never claimed that, just citing what St. Thomas believed in a solid firmament with waters above it, and said that this was consistent with the FE cosmology ... i.e. flies in the face of NASA cosmology of the ball floating around in space. You appear to be very educated, but I often see a lot of sloppy thinking and poor logic, where you conflate things. You often cite St. Thomas as your authority for ball earth, but then you don't accept what he holds regarding the firmament.
The video claimed that they were giving clear proof that medieval thinkers believed in flat earth. I am not willing to watch it again to quote the exact words.
I often cite St. Thomas to show that it is not likely to be contrary to Catholic teaching to believe in globe earth or to show how common the belief was in Catholic history. I do not cite St. Thomas as an authority on science. I rarely discuss the science aspects of this at all. I am interested in the theology and history aspects.