Problems uploading MP4 video to Facebook

I'm not new to posting videos to Facebook but am new to posting using Quick Time. I may not be wording all of this correctly:) However we recently purchased a GoPro 9 and when transferring these videos to my Mac they go to Quick Time Player. These videos will not upload to Facebook from Quick Time Player. My software on Mac is version Catalina 10.15.7. Quick Time Player is version 10.5. Can someone give me any suggestions. Yes my internet is very slow (thanks to ATT) but I did connect to a relatives internet last night whose is better and it still didn't work. I can upload to Youtube, but don't really want to go that route