Thanks for your question.
On the main map layer in the properties - there is a Base Map setting - you can change it there.
You will also note there is a link that brings you directly to the online doc.
The Geodata Layer will allow you to use another tile server: (TMS, WMS, GeoJSON)
GeodataLayer - visualizes background map data, either from a tile service or from a file, such as GeoJSON. The URL is an expression that is evaluated at each selection and data is reloaded when the URL changes. This way it can connect to external data services with dynamic data.
I am attempting to get a working example for you as well.
Let me know how you do
When applicable please mark the appropriate replies as CORRECT. This will help community members and Qlik Employees know which discussions have already been addressed and have a possible known solution. Please mark threads as HELPFUL if the provided solution is helpful to the problem, but does not necessarily solve the indicated problem. You can mark multiple threads as HELPFUL if you feel additional info is useful to others.