So far I have purchased, in no particular order.
Le mans 66 (Ford vs Ferrari)
Days of Thunder
Godzilla vs Kong
I'll get some more but this should keep me going for a little while.
I also have Netflix and Prime both that offer a little content in UHD but don't know if it's true 4K?
I did read somewhere that YouTube are finally going to have 5.1 on some content.
Lucy has stunning picture quality.