So, there's a thing in the forum, to avoid spammers I would say, was blocking my messages saying - you've reached your max for the first day
So I can give my update just now. I can confirm that this tutorial still works very well. I went back to your post from yesterday on installing java from the file downloaded on a different machine, and that worked like a charm. I was facing an issue where it would take for ever (2/3 hours) to start the server, and then would fail as soon as it started, and that got solved with installing the java version you pointed yesterday @Joakim_Sandstrom, thanks!
All the other steps to get the server to automatically boot when the machine starts/reboots, and accessing screen and all of that, works great.
The only thing not working from the original tutorial is the plugins, both don't work at all, links dead. Not essential to get it to work but reading the names (remove lag) I was interested on them.
So far, performance is good, tried only with 2 users, and runs fine, processor and memory around 50%, even with kodi playing live tv and a different machine playing a file shared by this rp. My only concern is the heat, it's on 54 degrees at the moment, not sure if that's not too high.
Anyway, thanks for all the support @Joakim_Sandstrom, your tutorial is great.