So this is an odd one, pressing DELETE to enter the bios does not work most of the time, especially, when coming from a reboot done in the OS, so its quite frustrating having to do a bunch of OS reboots and not being able to enter the bios.
I’ve tried with a normal USB keyboard (non-composite device), a wifi based usb keyboard (composite device of keyboard+mouse) and with the raspberry pi keyboard and mouse (keyboard is a composite usb device, and the mouse is attached to the it).
I’ve tried to increase the time the bios waits for a keypress and it does not help.
I just bought my Odyssey and I have the same problem with an Arteck keyboard / mouse wireless combo. Delete for Bios works sometimes while F7 for boot menu never.
Strangely I have a wireless Logitech keyboard which works for both the Bios and the Boot Menu.
The same Arteck keyboard works perfectly with the BIOS and Boot Menu of another PC.
Can you try to have one keyboard in a USB 2.0 connector and one in the USB 3.0 connector?
That seem to have solved the issue for me: after doing that and then using a single keyboard I can access the BIOS with a single key press.