Depends a lot on where you live. My village is pretty fresh cuz I update it lol. My impression is that it's quite good in western Europe, might take a month in major US cities, and probably years old in most other places. I think Indonesia, Israel, and Japan are decent as well.

It's as fresh as OSM databse : it depends.

You can take the initiative here.

Honestly in my experience is that in some parts of the world, or even particular neighborhoods even google maps is useless.

Even for routing google maps still fail with some one way streets directions.

CoMaps an end-user app, not an SDK.

How does it compare to AllTrails in America?

There is an outdoor map style which is more contrast to the general/default style, if that helps.

Half of the solution at least on Android is https://gpslogger.app. Then you need to find a way to render the data to a map, such as with https://dawarich.app. Looks like the last time I looked at that project (and wasn't quite sold on it) was 1.5 years ago, so time for a second look.

I have set up Owntracks with a self-hosted server, and the android app reports my location to it periodically over MQTT. I would prefer to use https://dawarich.app/ but last time I tried it it was clearly very beta-quality and not ready for reliable usage.

There is a subway overlay. And there is marked hiking routes overlay being in development. There is a also an outdoor-focused map style (some people call it a layer too).