When I download the Gaia topos, my old very cheap tablet used to take like an hour to download one area, depending on how big. My newer Samsung Tab A (2017) downloads much, much faster, only a few minutes for the same map as before. So it might just be your device.
I'm thinking it may be a combination of device and platform. Many features are rolled out to Apple products that are not available on Android for a year or more. I know that it is a small company, and it is clear that Android is not a focus for them.