In ArcGIS Pro it is possible to view multiple vector tile packages (vtpk) at the same time, overlaying each other, for example; landuse polygons with contour lines on top, each from different tile packages.
Is this same functionality available in Collector?
Collector allows for using one VTPK as a basemap, it doesn't support viewing multiple VTPKs in the same map. You can put all of your layers into one VTPK or create a Vector Tile Service (extractable) and take them offline.
