Were it mine, I would probably try to acquire/borrow a Dell Restore Disk and fix it that way.
If you do a complete wipe (ie. DBAN), you may eliminate a hidden partition on the drive that allows the Dell restore disk to work.
If you don’t care if the machine remains a “Dell”, doing a complete wipe and clean OS install would be fine.
I mention the above because sometimes an owner of a manufactured machine, such as a Dell, does a complete wipe and regrets it.
(usually because of lost software)
Maybe a Dell owner will chime in (or contact Dell), as there may be a “hot button” routine to engage the Dell Restore function.