Blue screen fatal error : video DXGKRNL - XPS15 W10

Thanks for taking the time to reply. 
I have ran Support&Assist regularly. Drivers are uptodate; no error message. 

Sorry but I am not familiar how to run diagnostics in BIOS? 
And not sure what is meant by DISM?

No worries. First let's start with running the diagnostics in BIOS. Start by shutting down your computer. Then while you are turning on the computer, constantly hit the F12 key. This should take you into a one time boot menu. There should then be a diagnostics option. Let it run and report back with the results. Taking pictures might be helpful in the process (in case you get stuck I can see why and I can see the diagnostics results).

Have you ran diagnostics in BIOS and/or SupportAssist? Have you tried running DISM?

I just did google Bios diagnostics and was running it. No error found including « additional memory tests » at the end of the test. 
ePSA: build 4306.17 UEFI ROM

system Bios: 1.24.0

will be running Dell online diagnostics an other time. 

Am looking also into DISM test but still need to digest the info!!

I ran DISM « ../cleanup-image/Restorehealth. Result ok

I re-run sfc scannow as suggested by Dell. Results „no integrity violation“

Full online Support Assist diagnostic OK

The XPS15 9360 is about 4 years old, used on’y at home. Due to travel it is used only from time to time!

I would say the problem showed up about 6 to 9 months ago. I cannot correlate the problem with either an update or a specific program. 

I do not have any fancy programs or apps loaded. 

Let see if it happens again although nothing wrong was identified or repaired during the various diagnostics 

Okay let's see if this issue persists after DISM. Also, how old is this laptop and when did the BSOD start occurring? (Was this an issue that occurred even when the laptop was new or occurred after that etc?)

Did you try to reinstall video drives directly from dell support page for your laptop?

Yes

ok, did you check memory dumps with bluescreenview and MS debugging utility? What cases bsod?

well it's up to you, what I may offer from my side is to have a remote session with you and check your configuration and system logs\dumps or you can download https://www.nirsoft.net/utils/blue_screen_view.html and make\upload here screenshot of what it'll show you after it'll be started.

No I did not check the data after blue screen crash. Would not understand the results!!!

I guess I will try to live with it until I change laptop!! 

Laptop is a Dell XPS15 CNX 95604 purchased 03/2017

4K Ultra HD

Intel  i7-7700HQ / 16!GB DDR4-2400 MHz

Windows 10 Home (This unit cannot be upgraded to W11)  

Thank you very much for the kind offer. 
I will try to find out how to get the data and paste it here today. 
For info I shall be away (without Laptop!) starting tomorrow.