Ok, so far so good.

I went through your guide and it worked all quite good. Had some minor issues to add the ashigaru user to sudoers group. I had to do it from the already existing dojo user, than it worked. And I had to allow the port an my ufw rules first to access it from my local browser.

I now can access ashigaru from my local browser (librewolf) but I only get some weird vertical color stripes all over my screen. I assume this has something to do with librewolf, but I don't know how to solve it.

Any ideas how to fix it?