After a few days this power setting does seem to have cured my crash and restart while sleeping issue. 
I originally posted about this back in August 2020 in a post by the same title (typo fixed, question mark removed). XPS 17 9700 crashes when sleeping - Googix fingerprint to blame?  A number of people with recently purchased XPS laptops reported that it was the same for them and the fix I suggested in that post fixed things for them, thus I now have next to vanishing doubt that there is something wrong with the Goodix fingerprint device.  I'm reposting as I have had a reappearance of the issue but this time less obviously causing BSODs. Dell replaced my motherboard back in the autumn and after a full OS reinstall everything seemed to be fine - no more crashes. Then a few updates later in the last few weeks I noticed that my laptop was sitting on a failed to restart recovery screen when I returned to it after it had been left idle and plugged in. This time SupportAssistant wasn't picking up the presence of a BSOD. I did a full reinstall again but the problem persisted. Eventually I went through the Event Viewer and found a reference to a dump, reinstalled WinDbg and found that the Goodix fingerprint reader was back presenting power management timeouts. (screen grab below - see linked post for details)  I've applied my workaround as many people also found that this worked and I'll post here in a couple of days time if it has worked again.  [IMAGE]
XPS 17 9700 crashes when sleeping - Goodix fingerprint to blame