One by Wacom does not work in Ubuntu 18.04.4

I have Ubuntu 20.04 installed on my computer. I have just bought Wacom One Medium to my kid, and it works flawless right out of the box. It is the newest linux, and an old and simple model of drawing tablet - I am not sure whether it would work with more sophisticated models, but this is pure plug'n'play experience. I hope this helps someone.

So I managed to figure out a solution and now my tablet is at least working with xournal, for example.

First of all, I updated my kernel from 4.15.0-96-generic to 5.3.0-46-generic following the steps described here:

https://www.linuxuprising.com/2019/02/how-to-install-ubuntu-18042-lts.html

I am only mentioning this here in case it helps someone else, but in my case I don't think this played any role.

The real problem seemed to be Secure Boot. Namely, a friend found this

https://github.com/linuxwacom/input-wacom/issues/77

to which my problem was a match, therefore I followed this

https://github.com/linuxwacom/input-wacom/wiki/Secure-Boot

and checked that indeed when I disabled my Secure Boot from BIOS the tablet worked. Then I followed the steps regarding the keys, and finally I re-built input-wacom from source following

https://github.com/linuxwacom/input-wacom/wiki/Installing-input-wacom-from-source

but now adding the secure boot keys, namely I used the command

if test -x ./autogen.sh; then ./autogen.sh --with-signing-key=/root/MOK.priv; else ./configure --with-signing-cert=/root/MOK.der; fi && make && sudo make install || echo "Build Failed"