HDR support on XPS 9360

I'm trying to get a clear answer on HDR support on my XPS 9360. It uses the i7 8550U processor, 16MB RAM with integrated UHD 620 graphics which 'seems' to support HDR, although getting clarity on that is 'challenging'.

The laptop itself has the 3200x1800 touchscreen panel and it is driving via USB-C

1. A Philips 346P1 3440x1400 panel with integrated docking station
2. A daisy-chained Dell P2717H 1920x1080 screen

Running shows me...

1. For the laptop panel
   1. Card name: Intel(R) UHD Graphics 620
   2. Native Mode: 3200 x 1800(p) (59.982Hz)
   3. Monitor Capabilities: HDR Not Supported
   4. Output Type: Internal
2. For the 346P1
   1. Card name: Intel(R) UHD Graphics 620
   2. Monitor Model: PHL 346P1C
   3. Native Mode: 3440 x 1440(p) (59.973Hz)
   4. Output Type: Displayport External
3. For the Dell P2717H
   1. Card name: Intel(R) UHD Graphics 620
   2. Monitor Name: Dell P2717H (DP)
   3. Native Mode: 1920 x 1080(p) (60.000Hz)
   4. Output Type: Displayport External

Yet when I look at Windows HD Color settings I see:

1. Internal display: Yes for Stream HDR video, but No for both 'Use HDR' and 'Use WCG apps'
2. And for both external display: No / No / No

Before anyone wonders whether the 346P1 supports HDR, you can read all about how it does on page 21 of the linked manual.

IS this simply a limit of the 620 chipset? I'm on the latest driver ... although I am on v27.20.100.9664 signed by the MS Windows Compatibility Publisher, while the versions on the Dell support site is slightly older at .100.8854. The installers are:

1. Intel-HD-Iris-Graphics-Driver_C1Y17_WIN_27.20.100.8854_A14.EXE
2. Intel-HD-Graphics-Driver_6D0DP_WIN_27.20.100.9664_A07_01.EXE

Both date from 27-Aug-22.

So I'm wondering, is HDR simply beyond the scope of the 620 and so I should simply give up on HDR on this machine?

hanks for any advice