So I've figured some stuff out, mainly about my projector and reciever (TR-NX787) that's in between the projector and LE.
It appears that the Intel 730 is putting out an HDR signal. It's just not sending the right meta data from the file -the BT2020 colspace, across the HDMI to trip the projector into the correct mode. Kodi itself knows that the content is HDR as it identified it in the tags. Maybe LE isn't enabling that with the Intel drivers or, the Intel drivers are lacking that feaure under Linux.
Now, looking back on things, 3D content is the same way. I remember I had a RBPi years back and when I played 3D content on that, the Samsung TV would automatically flip into 3d mode by itself, whether it was TAB or SBS. That was awesome. The 5040 is acting the same way with 3D content as it is with HDR. Because it isn't seeing the right metadata, it doesn't flip the modes automatically.
As for what the right metadata is or how to get the Intel GPU to send it. That's well above my paygrade unfortunately.
I can force the projector into BT2020 colorspace manually in the settings -auto is the default. I also dropped Kodi's resolution down to 1080p30. With that I get 36bit color reported by my TR-NX787, and the projector shows 12bit in the color depth field. This could be some kind of limitation with the Intel GPU dropping chroma and bit depth down to achieve the higher 4K resolution.
So because the BT2020 mode on the projector is dependant on the meta data being sent, it won't go there automatically. I also can't save a memory preset with that colorspace set in the projector, which would have made it a bit easier to go back and forth. So I am forced to flip the mode manually whenever I want HDR content. That sucks but the HDR collection is small so far.
There is a big difference in experience I must say. I'll bet it's even better on a full (aka newer) HDR system as apposed to my 2016 projector. And eventually, LE and Kodi will build on it's HDR support. But one can hope for a sooner than later metadata fix
Thanks for the help everyone!