Well thing is OSMand does have the trails and I can enable them in map view.
Maybe there is just misunderstanding on my side (I'm not an English native speaker)? I mean these official marked hiking paths. OSMand calls them "hiking routes" so I guess that's a different thing to trails?
Yes, these are pretty common in my area. There are hiking groups that maintain them, they are marked IRL too and are great to orient yourself (the marked trails are color coded so you know to stick to blue until you encounter red and continue on red path for example). Also makes it easier to plan routes andsee how to get to some landmarks. In some places, like National Parks, you it may even be mandatory stick to those and not go on unmarked trails.
So I guess those are indeed different things. Well that at least clarifies stuff for me. Hiking trails are all the various paths that are in the forest, and hiking routes are the marked ones.