I mean, sure? But I don't do that. For city driving OsmAnd makes a sensible route which sticks to main roads whereas Google Maps was getting so bad me and my wife stopped using it because it's choices were bafflingly weird, and would do things like "make 8 turns down residential streets, then obviously make a turn across the busy 4 lane main road you could've already been driving on".

Google Maps for whatever reason routes like a residential street and turn can be negotiated at exactly the speed limit the whole way through.

It's just OpenStreetMap, see https://wiki.openstreetmap.org/wiki/How_to_contribute

> I wonder, how difficult is it to make minor edits to the map data?

The map data is OpenStreetMap, so you can make edits via the standard OSM methods:

Web: https://ideditor.com/

Local: https://josm.openstreetmap.de/