The current version of ISO (202306) is not secure boot compliant. So, in order to boot using the ISO, you need to have a device with secure boot option disabled.
You'll get the above error when the device you using has secure boot enabled. So, you may try loading the ISO on another device where secure boot is disabled.
Red Hat do not recommend to make any changes to the BIOS settings as it may impact the regular boot. You can take help of any local technician to make changes with settings or if you want to try on your own, you can try at your own risk