Someone can correct me if I’m wrong but I think there’s only 4 file formats that can store HDR images: .HDR .EXR .TIFF and .PSD
Files like JPEG and PNG are not designed to store HDR images so they won’t work.
I’m not sure if GeForce Experience can take HDR screenshot in .TIFF format. But the last time I tried it, it takes PNG instead and it becomes washed out because it can’t convert the HDR signal to SDR.
Even if it can convert the signal successfully, the end result would be an SDR image anyway as long as it’s not sorted as .TIFF file.
Then there’s the issue of displaying them. What happens if it’s being viewed using non-hdr display? Does it have built-in SDR conversion like YouTube does with their HDR videos? So many questions.