DBAN is a MBR-only ISO and as such does NOT have a UEFI bootable mode - it is fairly old even though it still works, and doesn't have a UEFI boot option in it. You can take the approach of switching your BIOS/system to MBR, run DBAN, then switch to UEFI again. The data will still be gone on disk.
However, I may have an alternative to DBAN, if you're interested: Use an Ubuntu installation / Live USB disk as a base, then use tools in Linux already to erase the disk.
Instead of writing DBAN to a USB, there are tools you can use already in Linux, and can erase data with ease like DBAN does. Both the options I suggest here start with writing Ubuntu 18.04 or 20.04 Desktop LiveUSB to the disk instead (20.04 recommended). Reboot to that disk.
Then, ppen up a terminal in the LiveUSB and run sudo fdisk -l and find the hard drive in question. It should have an /dev/sdX type indicator (where X is a letter) or an nvmeXnY (where X is a number and Y is a number).
The dd approach
Then run this:
sudo dd if=/dev/zero of=/dev/DEVNAME bs=1024
... where DEVNAME is the device found in the previous set of commands.
This will run and overwrite your disk with zeros from start to end. Note that this will take a long time without any progress indicator.
If you are using Ubuntu 20.04 in your LiveUSB, then use this, which does have a status indicator:
sudo dd if=/dev/zero of=/dev/DEVNAME status=progress
The dcfldd approach
This requires you to first run in the LiveUSB these commands in terminal:
sudo add-apt-repository universe
sudo apt update
The program dcfldd is a modified version of dd in the Universe repository designed for work with forensics specialty so it has a lot of other tools and hash sum verifications to validate wipes and hashes. This also comes with status meters for progress, and reports as it goes (in Ubuntu 18.04, dd did not have this, so if you are using 18.04 in your LiveUSB for this, you may want to use the dcfldd option instead if you want a progress indicator)
It uses a larger block size (bs) by default, but is also more than capable of wiping your disks, and is an alternative to dd because it has status tracking and indications as it goes.
Similar to above, use:
sudo dcfldd if=/dev/zero of=/dev/DEVNAME status=on
What this does is runs dcfldd with the same options, except it defaults to the 32768 bytesize block size for how it processes. This also has a status indicator which we're forcing 'on' here.
This essentially does the same thing as dd, but is faster and has a guarantee of a status indicator.
