I have not seen such a plugin or feature in OSMAND (thus it may exist anyway). It have just gotten a Mapillary plugin, that shows where there are taken pictures. OSMAND can also record a gpx-track of where you have been (using a plugin).
As I understand, you needs a gpx-file that essentially shows all paths from OSM where there are NO Mapillary pictures? That is pretty hard to make, because pictures are not tied to a particular path. Usually they overlap it pretty well, if both the map and GPS are accurate.
What do you need such a gpx-file for? Why would a map with Mapillary sequences not do it? Perhaps I can figure something out that will help.
I have a Python script that creates a gpx-file with all Mapillary sequences for an area (gpx-to-area.py in https://github.com/simonmikkelsen/gpxutils).