It’s because OsmAnd has some serious issues searching for certain addresses. It’s not an OpenStreetMaps problem, but an issue with the app. Organic Maps is better. Magic Earth is even better. Note: only talking about address searching. OsmAnd still has a ton of other useful features.
If I need to use OsmAnd, sometimes I’ll copy the plus code from Google Maps, as that translates to GPS coordinates.
https://sh.itjust.works/c/localllama