Hello.
This is very dependent on the area that the map shows and your settings.
If describe the problem in general:
Online Maps, Real World Terrain and many other applications and services use OSM data, which creates a heavy load on the service.
What can I suggest to work around the problem:
1. Split one big request into few small requests, which will greatly reduce the load on OSM servers.
2. Add support for OSM Buildings.
https://osmbuildings.org/
3. Add support for Mapbox buildings. But to do this we will need to write a lot of code. In addition, Mapbox tile contains all the vector information about the tile, not just the buildings. This means that 95% of the data will be downloaded, loaded into memory, but will not be used.
All three ways are cache friendly, which makes it possible to implement caching of tiles.
I would choose the second way, because it is quite easy to implement.
Kind Regards,
Infinity Code Team.
Boost your productivity a lot and immediately using
Ultimate Editor Enhancer.
Trial and non-commerce versions available.