PS: Please consider donating something, anything to the guy - he really keeps delivering and has done a lot for Synology users, helping everyone get started with all things Docker!
I think the short answer there is a yes but the qualified answer is "it might be harder or have a gotcha"
I've used a few tutorials from here and they are usually on-point when up-to-date as this one is. They actually have walkthroughs on doing docker installs so I can only imagine the reason here is something to do with how they wanted set things up that made the container manager too much.
We are dealing with a setup where the general public will be hitting your NAS, this may be a way to secure things but I'm only guessing. We could try reaching out.
The thing is, people might not know that they have to look for the Docker setup. Now if they search for "Lemmy on Synology NAS" they land on this guide, telling them to use Docker.
The example docker doesnāt work out of the box and I suspect Synology has something interfering (thatās usually the case). Marius has some excellent guides that (nearly) always work on Synology.