I've found that running Windows 10 with HDR enabled looks awful, most likely because most apps and content isn't HDR enabled. But from what I can see, I seem to need to have it enabled in Settings for it to be available in games.
On my Apple TV I'm able to leave HDR turned off and only activated on-demand if the content itself is HDR. That seems the better approach. Is that option available in Windows 10 also? Or do I have to have it on all the time in the OS itself for it to be available in HDR content? Or even worse, do I have to go into settings and enable it every single time I want to use HDR content?