How to fix 'modprobe vboxdrv' error in virtualBox after restart?

Question

I know there is a very similar question: How to fix 'modprobe vboxdrv' error in virtualBox?

If I restart my server I have to do following:

sudo apt update
sudo apt install --reinstall linux-headers-$(uname -r) virtualbox-dkms dkms    
sudo modprobe vboxdrv
sudo modprobe vboxnetflt

Without this workaround I can not start my virtual machines on the server. I do not understand why I have to do it again and again and again after each restart of the server.

An easy hack would be, to create a service file inside my systemd which will reinstall it and load both kernel modules. After this service file is finished the virtual machines could be started. But that is not a good solution. I want to avoid that I have to reinstall it each time.

Any solutions? Thanks in advance.

dkms status
virtualbox, 5.1.38, 4.4.0-201-generic, x86_64: installed
uname -r
4.4.0-201-generic
lsb_release -rd
Description:    Ubuntu 16.04.7 LTS
Release:        16.04

So each time I restart the server I got:

Kernel driver not installed (rc=-1908)
The VirtualBox Linux kernel driver is either not loaded or not set up correctly. Please reinstall virtualbox-dkms package and load the kernel module by executing
'modprobe vboxdrv'
as root.

So the service of vboxdrv delievers

service vboxdrv status
● virtualbox.service - LSB: VirtualBox Linux kernel module
   Loaded: loaded (/etc/init.d/virtualbox; bad; vendor preset: enabled)
   Active: active (exited) since Do 2021-01-28 14:02:19 CET; 5 days ago
     Docs: man:systemd-sysv-generator(8)
    Tasks: 0
   Memory: 0B
      CPU: 0

If i try to setup vboxdrv I got:

sudo /etc/init.d/vboxdrv setup
sudo: /etc/init.d/vboxdrv: command not found

Also I tried:

sudo apt-get install shim-signed
sudo su
openssl req -new -x509 -newkey rsa:2048 -keyout mok.priv -outform DER -out mok.der -nodes -days 36500 -subj "/CN=[name of key]/"
/usr/src/linux-headers-$(uname -r)/scripts/sign-file sha256 ./mok.priv ./mok.der $(modinfo -n vboxdrv)
mokutil --import mok.der
EFI variables are not supported on this system

So how can I solve that problem with EFI/UEFI secure boot on Ubuntu Mate 16.04?