Dear Katrin, "It's complicated", as they say.
Started last September after a long illness, began walking 'follow the arrows' walks. Reading a map to get to the start was a drag when the start is in a hidden barn or seemingly disused football changing room. The walking/ cycling shop suggested Garmin Oregon with FreizeitKarte-OSM maps.
With the OpenStreetMap scrolling as one walks past, noticed missing or out of date info, collected notes to amend and sent those in. Was invited to place those notes in relevant positions on the map, then to edit those points, with someone from a distance 'looking over my shoulder', and to upload supporting photos to Mapillary.
Some observations are not in the remit of a map, like a barely visible Grande Route-marker or nominating thorny bushes on a public path fortrimming. Looking at classification as walking / cycling path sometimes wonder how well one could cycle on such a muddy track.Or cycling to a walk along part of a GrandeRoute find missing turn markers.
Describing OpenStreetMap as "a wikipedia-style walking/ cycling map/ guide" pre-empts further questions : that may sound unkind, but aim is to regain health, strength and stamina through sustained exertion - walking isn't exertion, but at this stage ... .
You mentioned 'other projects'? Could you elaborate, please?