How about using maps provided by third parties?
The one provided by "open street map" worked well for me in terms of resolution. (find the attached file please.)
name = 'openstreetmap';
url = 'a.tile.openstreetmap.org';
copyright = char(uint8(169));
attribution = copyright + "OpenStreetMap contributors";
displayName = 'Open Street Map';
This script adds "open street map" to your geobasemap.
Once you run this, you'll get a new list of base maps to choose from - that has the open street map in itself.
You can change the base map by