If it looks washed-out it may be because HDR is not properly enabled.
You have to enable it in Windows first, then in the game (started after enabling it), you should have a setting to enable HDR, then it should look nice, even in the menus.
The default settings are good enough (50/140/1000) but then you might want to set them to fit your TV and playing conditions (my TV expects 4000 nits so I set the last setting to 4000 and the second to 120-160 depending on ambiant lighting).
If it's still washed-out, do other games have good HDR ? Mostly UWP games like Forza Horizon 4.
Also, if you have some overlays injected into the game, maybe they don't support HDR well and mess with it ?