How to let my Dell laptop boot from USB flash?

have you treid some free windows password rest tool which supports USB 2.0 and support UEFI BIOS, like ntpassword, passfolk saverwin…i used it to remove my admin password but not sure if it works for you.

https://pogostick.net/~pnh/ntpasswd/

https://www.passfolk.com/windows-password-recovery.html

i suggest you to buy a latest USB drive…