there is no need to run "sudo /usr/sbin/vboxconfig" - that is the Oracle way to install VirtualBox and is not the OpenSUSE way.

the VirtualBox install for the OpenSUSE host is:

sudo zypper in virtualbox virtualbox-kmp-default virtualbox-qt

reboot to install the kernel part

for the OpenSUSE guest

sudo zypper in virtualbox-kmp-default virtualbox-guest-tools

reboot to install the kernel part

For all other guest - use the menu to install the guest additions if Windows - Most Linux guest already have Virtualbox guest code installed (ubuntu, mint, manjaro all do)

Secure boot and UEFI are already in the OpenSUSE repository installed with zypper.

The Oracle code does not have signatures for secure boot. It looks like you are trying the Oracle code.

I have managed to still fetch the retracted (? where is this exactly
documented and talked about? ....55.22  kernel-default and -devel and
what not package

so vboxconfig now kind of runs builds compiles or something but fails
at the end? is the reason maybe that this physical hosting system is
using uefi and secureboot both activated?

-------

Building kernel modules...
Kernel modules built correctly. They will now be installed.
insmod /lib/modules/5.14.21-150500.55.22-default/weak-updates/extra/vboxdrv.ko
modprobe: ERROR: could not insert 'vboxnetflt': Key was rejected by service
insmod /lib/modules/5.14.21-150500.55.22-default/weak-updates/extra/vboxdrv.ko
modprobe: ERROR: could not insert 'vboxnetadp': Key was rejected by service
Kernel modules are installed and loaded.
-----------

how to run virtualbox on opensuse 15.5 with a uefi and secureboot
activated system?
ty.