Windows 11 rollback to 10

Please click on link below, hopefully it will be a help to you.

Factory Image Restore Windows 10 (Official Dell Tech Support)

https://youtu.be/TpkLNYcpJPM

Unfortunately, it appears that cannot work as the windows O/S was loaded by Dell on a new machine. therefore there is no rollback

G

Once a computer is upgraded to Windows 11, you have 10 days to utilize the rollback function to move back to Windows 10 while keeping files and data that you brought along with you.  After 10 days the old version of Windows is removed to free up space on the hard drive.

How to Roll Back Windows 11 Upgrade to a Previous Operating System | Dell US

After 10-day period, you'll need to back up your data and do a “clean install” in order to move back to Windows 10. I suggest creating a windows 10 installation media from the Microsoft website in link below. 

Download Windows 10 (microsoft.com)

You'll need a blank USB flash drive with at least 8GB of space if you want to create windows 10 installation media

How to Create Windows 10 Installation Media (Official Dell Tech Support) - YouTube

Also, 

Factory reset, restore, or reinstall Microsoft Windows on a Dell computer | Dell US

Hi. The other issue is the computer does not have the USB boot enabled in bios. there appears no way that it can bott from a USB. (this laptop had no DVD/CD drive)

Pete

When you create a UEFI-bootable USB flash drive, you will be able to boot from USB.

Disable Fast Start in Windows 11 if there is such a thing.

Shut down Windows 11.

Insert that USB flash drive. 

Turn on laptop.

Quickly tap F12 to get to one-time boot menu.

Tried that. No dice, The boot sector will not accept USB as a Boot option..

pete