XPS 8940, SA update corrupts Windows

I have a Dell XPS 8940 w/NVIDIA GTX 1650 put into service Oct. 2020. Operated without issue for approx. four months until a Dell update when, upon rebooting, the boot screen would display (Dell logo with rotating circle) but then displays a black screen when it should display the Windows logon display.

Over the past three and half months...

- Dell attempted to correct remotely w/o success

- Windows was reinstalled multiple times and the XPS would operate until Dell and Windows updates were done whereupon the problem would re-occur

- Unit was returned to Dell where they replaced the NVIDIA card and reinstalled Windows - worked until Dell and Windows updates were done and then the problem re-occurred

- Dell had an onsite rep visit, replaced the NVIDIA card again and the motherboard (did not reinstall Windows) - did not resolve the problem nor did various changes to BIOS settings related to graphics by the rep

- Dell provided a refurbished replacement, same specs except an Intel I11 vs I10 CPU and an NVIDIA GTX 1660 vs GTX 1650 graphics card. Repeating history, the unit operated correctly on initial startup and after Windows setup, but after Dell and Windows updates, the problem re-occurs

Attempted a Windows reinstall from installed files and the Dell support utility reported it could not do this, so reinstalled Windows from a USB recovery drive created from a Microsoft download. After setting up Windows, it installed a cumulative update. Then installed Dell Support Assist, ran it and selected updates. Interestingly, it had only two updates that notably did NOT include any driver, firmware or BIOS updates as it had in all previous cases. To my surprise, the XPS continues to operate afterwards.

Evidence points to Dell Support Assist being the culprit in corrupting the system. In all previous incidences, Support Assist had installed graphics drivers (Intel and NVIDIA), BIOS update and other firmware updates. In this latest case it did not and the problem, so far, has not re-occurred.

My working theory at this point is to uninstall Dell Support Assist and this seems to be supported by others' experiences I've read of within the community of Support Assist causing problems, including one that matches the symptoms I've seen.