How to properly set up analytics for a mobile application?

Question

Analytics

Salute, habravchane.
I encountered such a problem when tracking installations of a mobile application, the solution of which I hope to receive. Can you help me?
So, for the first time I decided to set up a couple of analytical services to track effective promotion channels:
1) AppsFlyer
2) Flurry.com
Putting tracking links for each channel/banner was not difficult. But since I wasn't only driving installs through banner placement and contextual advertising, I had to deal with this. By posting reviews of my application on various thematic portals, I came to the conclusion that the most effective portals are essentially application catalogs. And a link to download applications for them is given from the server of the portal itself. That is, for some reason it is easier for people to download the application not from official stores (Google Play, AppStore, etc), but directly from the portal. This way they get an executable .APK file from the link, the installation of which is ultimately not tracked by any of these analytics services.
So the question has matured: what application analytics service makes it possible to fix such settings and how to configure it (or configure the 2 services I mentioned above)?
I contacted the technical support of many services, I did not receive an answer to this particular situation.