Not sure if there’s a better place to ask this. From what I understand, OsmAnd~ is basically a community-run version of the otherwise subscription-based OsmAnd+
To add POIs and make other changes to Open Street Map, I need to log into an editing account of sorts. Will this be fine or could my access to the app get wrecked in some way? After all, I am not subscribed to the “official” service.
You should ask on the OSM self-hosted stack exchange. It will be better indexed by search engines so others can find it
https://help.openstreetmap.org/