I'm a beginner at this stuff so bear with me, I'm trying to edit HDR screenshots from an Xbox One X and Windows 10 games on Photoshop 2020, now the images produced when taking a screenshot are in .jxr format, these files do not open in Photoshop without a plugin, so I downloaded the Jpegxr plugin from microsoft and installed it to Photoshop, and now it successfully opens the .jxr photo, however, it displays very overexposed and not in the way it originally looked.
I dont know if this will help narrow down the issue, but if I display that same .jxr photo in the Windows 10 photos app, it displays in that same overexposed way for only a brief moment, then it displays properly in HDR.
I have this same problem and nothing but "silence" from Adobe which is a little disturbing. Both professional and consumer usage is starting to be more and more HDR10 based. The JXR files are clearly HDR format and contain over 2X data as the PNG version, so what's up with Adobe?
However, unlike you, the Win10 Photos app does NOT display the HDR image correctly, it's dull as if the contrast and brightness were removed which is exactly the opposite of how it shows in Ps where it's blown out and way over exposed.
But the real irony in all this HDR mess (from both Microsoft and Adobe) is that the Windows Game Bar capture that generates the JXR files looks "correct" in the Game Bar Gallery preview window, but not in Photos app nor in Adobe Ps.
If you take a look at all the related posts to HDR and the complete lack of response from Adobe it doesn't bode well for those of us that use HDR10.