I've been impressed with OSM's https://opentrailmap.us/

but it doesn't have the ratings/uploads/discussion that something like alltrails has. might be cool to have a fediverse/activitypub application using OSMtrails data.

Osmand has official hiking and biking routes but not like what you or I want. Wanderer is the immich of routes.

Wanderer is pretty fun, more user curated things, some are shitty some are high quality, depends, plus you can just contrubute your route too! And the fact that it's activity pub powered is a nice bonus

I haven't used alltrails since they started requiring login. I generally find trail information from the website or in person visitor center of the relevant park/conservation district/forrest service/whatever. Sometimes I'll map out those points on Organic Maps manually if I know I'll need to reference the map while out of cell signal.

I can't help on the open source side but I find Komoot to be more user friendly and open. For example you can download GPX files without a subscription to then make trail bookmarks in open source apps like CoMaps.

I've enjoyed Hiking Project, but my needs are pretty simple and don't know if it has the features you are looking for