A BIOS error of time not set cannot really have to do with Windows 11 vs 10. And even if the upgrade caused it, a reinstallation of the OS (which isn't at all yet loaded at this point of the error) won't fix it.
What happens when you press Continue on this error/warning page? Doesn't it boot?
What is it? You can try the following https://www.dell.com/support/kbdoc/en-us/000137978/supportassist-time-of-day-not-set-error-seen-on-start-up-on-dell-mobile-systems
Had the same issue a year ago. I honestly don't remember the exact steps. But paid $99 to Dell support. From I recall we loaded onto an USB stick a windows 10 recovery and then somehow went to the windows startup repair(Though i can't seem to get there. ) and selected the USB with the loaded files and erased current version of 11 and reinstalled W10.
Did you set the BIOS clock? Is your clock battery dying?
I should be more specific seems like that's one of the random errors that pop up. While writing my post here
That was the current error. Most times the windows boots all the way to the sign in page for a user but the keys are frozen and I can't enter any passcode. Or ever if enter the passcode it just loads to log by the user sign-on for hrs. So I end up restarting the windows multiple times until I can get it to boot up properly.
Last year when installing w10 again the laptop worked just fine. Now it forced upon me w11 and causing the same issues. At this point I'm ready to get a new laptop
As this current dell laptop is slow like a snail and just outdated since 2019.
But for the time being if I can get it back up and running I would until I find a new laptop.
Safe mode loads fine. Just couldn't get the windows key and bottom bar to load. So no internet or search functions.
Everything is backed up to one drive. So nothing that I need on my windows computer. Don't care to wipe or reset it.