Hi,
I think so, unfortunately 
ART does support 10-bit (and more) output in various formats, that you can then view on HDR screens (see this page for details), but the app itself, and the whole ecosystem it relies on, is not 10-bit ready. There was also another recent thread about this where you can get more info about the current situation on Linux: https://discuss.pixls.us/t/true-10-bit-color-depth
You might have better luck with vkdt. Ping @hanatos