The Ps5 will be better.
I only use the Playstation to watch movies and they offer a very good picture quality. I do not know about xbox.
Only to watch movies is at least currently the XBox better - because you can play synonymous 4k UHD Blu Rays (which, of course, but only with a 4k TV brings).
I have a 4K TV.
I bought them then, because the Xbox One S at least was cheaper then the cheapest 4k BluRay player. It is only with the Xbox One S (and Xbox One X). The original Xbox One can't.
I'll remember! Maybe I'll get an Xbox.