Hello,
I’ve waited for some time before posting here, but since the problem hasn’t still been fixed, here it goes in case someone could give it a look. You can find the original post in https://aur.archlinux.org/packages/nomachine/#comment-743370 . The problem, in essence, is that it seems that the moment I updated RPI/ALARM to from latest 4.x to 5.x kernel, NoMachine stopped working (it was working flawlessly for months with 4.x kernels). For convenience, I’m reproducing my original post below (attached).
thanks for your help.