Hi Noel,
Thanks for reaching out to the Microsoft Community. I apologize that your Surface device failed after the update. Here are the things you can do to get it fixed.
1. Force a full shutdown by draining battery from a continuous boot loop. Once it’s dead, connect the power and try power it on again by holding volume up + power for 15 seconds.
2. Force a Windows Recovery by turning it off and on 3 times in a row to trigger the Automatic repair.
3. Use a bootable USB at least 16gb in size. You will have to create one from a working pc or laptop using the Media Creation Tool. Then boot with Volume down + power to access the recovery options.
4. If nothing works and the BIOS/UEFI is still not accessible, you may need to proceed with Out of Warranty Service via this link:
Get service for your out of warranty or damaged Surface - Microsoft Support
Or
If you have very important data/files that needs to be backed up, have it serviced by an authorized or third-party servicing centers.
I hope this information is helpful. If you have any further questions or need additional assistance, please reach out and I will be more than happy to assist you.
Cheers!