XPS Issues with HDMI etc.

I am hopping someone with an XPS 9570 can help me.

My brand new XPS 9570 arrived in a pretty poorly state.  Initial issues were:

1. Colour saturation was massively overly saturated as to be painful.  No matter what settings were applied in "Dell Premier Color" the situation could not be rectified.  Red's were particularly bad
   
   
2. HDR video enabled in Windows Settings, but no HDR videos would open.  This applied to all apps; Edge, Chrome, Netflix etc.  Videos appear to start to load then the app (any of them) would crash
   
   
3. Thermal throttling... CPU and iGPU were throttling under even light load... performance was absolutely abysmal with all cores, GPU and VRMs spiking at near shutdown temps
   
   
4. Missing key strokes when touch typing.

So now having spent a good 30+ hours trying to fix the thing here's where I am:

1. A complete reinstall of windows using the inbuilt "reset this PC"
   
   
2. Downgrade of the intel driver to an earlier version from Dell (albeit not ones published on Dell’s driver site – found a side-link.  Intel drivers refuse to install as have to be from Dell).  The latest version from Dell removes the Intel Graphics Control Panel and seems to introduce much of the saturation issues
   
   
3. Manual reinstall of Edge using DCIM and SFC.

Since doing all of the above I have one remaining issue from the original list a couple of new ones!

1. Thermal throttling; CPU and iGPU are throttling under load.  CPU core 2 appears to be worst hit with regular 100c temps causing the whole package to throttle back. I do now have to load up the CPU and the Nvidia GPU in order to experience this.  The challenge here is that it occurs regularly when gaming, fortunately I don’t game much but the point is that the thermal design of the laptop is not sufficient for the components.  
   
   It would be great to get an honest answer from Dell on this design issue with the XPS 15 9570.  It is understandable that performance has to be compromised for the form factor.  Note there is plenty of Internet content that implies this is the case.
   
   Does anyone have an suggestions on this?  Have looked at ThrottleStop etc. but not convinced.
   
   
2. HDMI audio; can only get Stereo over the HDMI 2.0 port... this cannot be right.  The laptop is connected to an LG OLED 4k HDR (HDR10/Dolby Vision) panel, which in return is connected to a Denon Dolby Atmos AVR.  The panel and AVR support every Dolby standard you can think of and are "known good" configurations. 
   
   In Windows the LG appears quite happily, as does the AVR if I bypass the LG (as have tested both configurations).  However 5.1 an 7.1 options are greyed-out, the sound control applet/control panel only shows stereo.
   
   Things get worse when you try to enable Dolby Atmos using "Dolby Experience".  It will happily enable "Dolby Atmos for Headphones" after installing the "Dolby Experience" app from MS Store, then following the instructions to enable "Dolby Atmos for Headphones" in the "Spatial sound format" drop-down... HOWEVER... try doing this for "Dolby Atmos for Home Theaters" and the option NEVER appears in the "Spatial sound format" options.
   
   I have tried everything I can think of and/or find on the Internet including various versions of the Realtek audio driver (from Dell and from Realtek)... various versions of the Intel GPU driver (as this is over HDMI the display and audio are controlled by the "Intel Display Audio" driver... and rolling back the Realtek driver to the standard Windows "HD Audio" driver (which doesn't work at all which was surprising as this is a universal driver that works with just about every audio card).
   
   This cannot be right... an HDMI 2.0 equipped ultra book with an Intel UHD and Nvidia GPU should be able to output at least 5.1, and Atmos should be able to be enabled.
   
   I really need this issue needs to be fixed.
   
   
3. Finally, HDR.  The laptop screen is not really HDR.  It's close and HDR content looks "better" than SDR.  What makes this really interesting is that it exposes that Windows HDR isn't really HDR, certainly not HDR10/UHD Premium/Dolby Visions standards compliant. It's more like "wide-ish gamut SDR".  The next issue is that the HDMI port is only a 2.0 port, as such you cannot output HDR content via HDMI, well you can but only at a refresh of 30hz which is unusable and also not HDR compliant so no HDR panel picks up the content as actually being HDR (as it's not really).
   
   Does anyone have any suggestions for a USB-C/HDMI 2.0a adapter to overcome this issue?  I have a feeling it's not possible, seem to remember seeing somewhere that the 9570 is DP1.2 over USB-C as such even with an HDMI 2.0a port it would still be impossible to output HDR.