OpenStreetMap is just one big public database, things you contribute to it are seen and shared with all. As you suggest, it can be considered the “Wikipedia of maps”.

I make paper maps of an area that have details not appropriate for inclusion to OSM, which sounds a bit like what you would like to do. My production process is to use OSM data on one layer and then my organization’s private stuff on another layer which I believe meets the requirements of OSM for not commingling the data. And, of course, I credit both OSM and its contributors and the people who contribute the data for the private organization on the printed map. If/when we acquire data appropriate for inclusion in OSM then we add that data to OSM rather than to our private database.

Perhaps you could setup a process/system similar to what we have done for your maps that have data you don’t want editable by others.