Does CoreElec 9.2.8 / KODI Support HDR?

Had this setup, maybe 5 yrs, no real issues except I never managed to get 10bit HDR BT.2020 to work, I always have to get 10bit SDR BT.709, else everything looks rather flat and greyish.

TV says it supports HDR 10bit (TCL 55R615) and kinda just revisiting the issues after all these years.

Got the Beelink GT1 Ultimate, HDMI2.0a (certified) cable to the TV, no AV boxes or PlayStation or anything. Just an ethernet cable from my NAS for media files.

So… where’s the weak link?

Beelink? TV? Kodi?