How to properly install VirtualBox 7.2.12 on Debian 13 with secure boot (error loading/signing kernel modules)?

Gist:

So I tried following those instructions, but the modules don't seem to be signed, and vboxpci is not even installed (as per modinfo vboxpci). I just removed VirtualBox and reinstalled it via the Linux .run installer, and vboxpci is not installed, so how can I proceed?

I followed this tutorial if-not-true-then-false.com/2026/install-virtualbox-on-debian/2 and mokutil --test-key was affirmative, but vboxpci is not found still (I did add user to vboxusers group), and the other modules say parm: disabled:Disable automatic module loading (int). That means they should load automatically? lsmod | grep vbox returns nothing.