Though a different BIOS .. this may help:
https://www.asus.com/us/support/FAQ/1013017/ This DISABLE SECURE BOOT is something I forgot actually.
So stay with CSM enabled, stay with UEFI enabled, but secure boot disabled if possible, see if DVD option appears after reboot / into BIOS.
Also Im not sure on your board what F key gives you the boot order menu as system boots allowing you choose what to boot from, maybe F12 or F11 before you reach the windows load screen, just after the motherboard splash screen. With Secure Boot off this might work