What are your settings? Have you tried the settings I posted for Movie HDR in the settings thread? Your white level nits are way too low. How are you measuring them?Was it at least tracking the proper curve for luminance? Not behaving like the above sample I provided?
This is giving me a headache, as I've been sitting with this for a week trying to figure out what to do with this. It's just not really correctable as I see it. I tried some wierd settings before but peak luminance is still only half of yours or the advertised HDR1500 this was sold as.
EDIT: Tried another picture mode other than Movie in HDR.
Dynamic produces a fantastic ~975Nits. But this picture mode can't be adjusted and has a fun cool 10000K Color Temperature with "Standard".
Standard: only ~350nits