Please, add support for Dolby Vision!

You can also follow this guide for replacing the mpv.dll

Have you also edited your mpv.conf?
You need to add
vo=gpu-next
and the tls-ca-file line, you find in the post above.

Either way it should definitely work with a upstream mpv.dll.

But keep in mind the DV tonemapping will only work for specific DV profiles. The one you find on an UHD Bluray is not one of them.