On many Dells (and other brands), I have wiped the drive and performed a clean install of Windows.  You don't need to do a "low level format". You can simply use diskpart to erase the drive during the Windows installation process.  I don't understand what you mean by "bios reset to factory settings", since Dell is the factory and bios includes specific Dell entries. As for "without registering with Microsoft for the privilege of MS unwanted gunk", you don't need to register with Microsoft. You may install Windows 10 without a Microsoft account. You will need to download drivers for some hardware from Dell and possibly from component manufacturers. Drivers provided by Windows installation and Windows Update may not cover everything or may not be optimal. If you need warranty support from Dell, they may want you to install some Dell utilities. Yes, you could restore the factory image, provided you create an image of your current system so that you could restore it later. BTW, some Dell-provided apps and drivers are useful. For example, without Dell Quickset you'll lose some methods of accessing media key functionality, and you won't have the Dell entries in Mobility Center. Without Waves MaaxAudio or similar, you'll lose some audio features.
I have Optiplex 7090 sff, i7(10700/8core/2.98-4.8ghz,65w), 16gb ddr4, M.2 2230/512gb pcie nvme class 35 ssd For 18 months I fought off 'n on with above regards removing ALL traces of Dell/Win code. Ultimately, 100% HD low level format + bios reset to factory settings. IOW, I admitted defeat to my abilities in dealing with the factory ssd build. I learned that by downloading factory re-setup s/w, the machine could be as when I bought it. Given the ability to effectively wipe away one's lame attempts at thinking one can make the beast become what I wished by a restore to factory setup... Does anyone see any problems in doing a rebuild to what I need instead of all the overheads acquired by using what Dell thinks I must use... I would think that 'should' H/W issues be met, Dell would firstly a wee bit annoyed with my taking over my machine... This would require me to do total factory image re-setup, presumably prior to asking for support, YES? In-A-nutshell, great H/W and EZ to upgrade etc. BUT I seriously only need Windows 10 (minimal installation without registering with Microsoft for the privilege of MS unwanted gunk) Just need Windows to run 2 or 3 utils to allow me to make a living! also speed without any (as much as poss) bloatware from Dell or Microsoft! All comments gratefully appreciated 
What forseeable issues IF buy new XPS & then total nuke ssd then do minimal 
Win10 install?