I run Win 10 on my XPS 8930 and updated to BIOS 1.1.18 tonight via the F12 menu with no problems. If you're updating BIOS outside the OS, the version of Windows shouldn't matter. Is your wired USB keyboard connected to a rear USB2 port on PC? That's where mine is connected. Plug the USB stick with only the BIOS .exe file on it directly into the PC with power completely off. Don't use a USB port on the monitor or elsewhere. Then power PC on and immediately start tapping F12. Don't wait to see the F2/F12 prompts on the screen. Just start tapping F12 as soon as you power on...
Cannot install BIOS update 1.1.18. I have always followed Dell's instructions and ran in Windows and never had a problem. By the way, I am running Windows 11. If I run the update in Windows like I usually do, I get the popup: You are attempting to open a file type 'system File' and that's it. It doesn't go any farther.  I tried copying the update to a USB drive to install via the BIOS, but when I try to boot I can never get the F12, or even F2 to show on the splash screen. I installed a wired keyboard and mouse and I still can't get into the BIOS. With the wired keyboard, I get an error that it "can initiate keyboard". So it looks like there is no way I can even get into the BIOS for anything. That's a first for me. In other words, is Windows 11 security preventing my getting into the BIOS, or is this a problem with the BIOS update 1.1.18?
XPS 8930, BIOS 1.1.18 not installing