Geo Data Collector supports Vector Tiles inside MBTILES or GPKG SQLite databases
Vector Tiles are Protocol Buffer Format (PBF) serialization of the data and only what’s in view is shown so it’s very efficient
We currently are not supporting user GL JSON Style but we have basic style/symbology tool
If you want to have many overlays for reference while you are collecting data then please convert your GIS Data into vector tiles.
You can use QGIS Desktop or command line tools like: OGR2OGR or Tippecanoe to create vector tiles.
In addition, if you are an ESRI user you can convert their proprietary VTPK Vector Tile Package format into GPKG/MBTILES via some python sripts.