If you're still stuck, I’ve built a tool that automates the entire APK build process on desktop (Ubuntu/Windows), including Buildozer setup and .spec configuration. It might help eliminate the build errors before you even reach the emulator stage.

If you'd like to see how my build process works: I made a short YouTube video that walks through each step — from a KivyMD application to a finished APK using Buildozer. [YouTube link]

It might help — and I’d really appreciate any feedback, since I’m currently testing the tool with real projects.