NUC6AYH has HDMI 2.0 port (MCDP2800 LSPCON), J3455 Apollo Lake SoC with Gen9 Graphics. It should be capable to support HDR in Linux.
Windows HDR support is irrelevant, Gemini Lake also doesn't support HDR in Windows.
On my NUC6CAYS build from Post 502 works for HDR but like others it sometimes goes to blank screen.
HDR dont work if I select passthrough audio though.