@J-Hilk It all looks fine to me as well, this is why it's even more difficult to find the issue. Oh well, guess I have to spend more time on this than I had planned to. Thanks for all your help tho, I highly appreciate it! :)

Newer versions of Android are able to read native libs directly from the apk without extracting them if they are stored uncompressed in the apk. This is done to save disk space on the device, and the new default during apk creation, but Qt 5.12 does not handle this. To compress native libs again add android:extractNativeLibs="true" in AndroidManifest.xml to the application tag.

You define your value as a string, which is where the result is collected. Don't want a string, fix the software.