.mov alpha channel can't open

hello does any one knows how to open an animated video on final cut?
I downloaded son videos with alpha channel and it appears on my downloads and I am able to see it but quick player can’t open it. nor final cut either? please help?

Hello! Mac OS dropped the “QuickTime PNG RGB + Alpha” codec last year. Authors had to resave their items to “QuickTime ProRes 444 RGB + Alpha”. Perhaps author of the item you bought forgot to do this.
If you have Mac OS Catalonia, then this may be the problem