I want to make a map with an OSM base layer, visualised together data from another source (for example elevation data).
With QGIS I want to add vector layers, based on OSM (via tags). For example: roads or points of interest.
With this product, I would like to be able to:
publish it online, possibly as an interactive variant
I do not believe you are required to share any data. Only the OSM-based vector layers would be a derivative database, and this kind of filtering is likely a “trivial transformation” that is exempt from the share-alike requirements.