See docs/INSTALL.md

Disabling unity builds and reducing threads should help to build the project.

Do you have Qt 6.7 installed? There is a known issue with it. If yes, downgrade it to 6.x

Do not click on the root item in the download dialog. It will try to download all countries at once and freeze the app. Click and download only the necessary regions.

There are routing tests. They work without UI. You can benchmark them.

You can disable R8 for android in build.gradle, it is not needed/irrelevant to profile release C++ code for Android.