"Error verification failed" booting RHEL 9 Beta for install

I am getting the error "verification failed: (0x1A) Security Violation" booting RHEL 9 beta from an install disc. I found the following.

UEFI Secure Boot: system fails to boot with "Verification failed: (0x1A) Security Violation - Red Hat Customer Portal
https://access.redhat.com/solutions/5395851

1878773 – System doesn't boot and prints "Verification failed: 0x1A Security Violation"
https://bugzilla.redhat.com/show_bug.cgi?id=1878773

I have multiple GRUBs (see below) and I suspect that is the cause.

I created the installation disc by downloading the file:
rhel-baseos-9.0-beta-1-x86_64-dvd.iso
And then burning it to Blu-Ray using Windows.

I could not find where in my BIOS to disable Secure Boot. I did change the OS Type from "Windows UEFI mode" to "Other OS" and then when I perform the diagnostics in the knowledgebase article I get:

root@Sams-ASUS sam]# rpm -qa shim-x64 grub2-efi-x64
shim-x64-15.4-2.el8_1.x86_64
grub2-efi-x64-2.02-106.el8.x86_64
[root@Sams-ASUS sam]# yum check-update grub2-efi-x64
Updating Subscription Management repositories.
Last metadata expiration check: 0:42:40 ago on Wed 22 Dec 2021 03:19:14 AM PST.

Also when OS Type is "Other OS" I can boot the RHEL 9 disc. I assume I do not want to use "Other OS" normally. Am I correct that it would be less secure?

I think the problem is that I have multiple GRUBs. I have the following physical drives:

• 1 hard disk
• 2 SSDs
• 2 portable USB drives
• 2 thumb drives

I have Ubuntu installed in a portable USB drive and RHEL 8 in another. I intend to replace the RHEL 8 with RHEL 9 eventually; I will eventually install RHEL 9 in a new SSD that is probably still out at sea awaiting delivery. I have a Puppy Linux installed in a tiny partition in a SSD. So my UEFI Boot menu includes GRUB(?) entries for Ubuntu and Lick.

Could the other GRUBs be causing a problem? I want to keep them if possible but all Linux installations are disposable if necessary.