From a discussion in the mailing list:

However starting with 5.14 something changed in the qt android setup,
e.g in aqt qt-install you don't specify the architecture anymore:

android:              Qt 5.14:

android (optional)

Qt 5.13 or below:

android_x86_64, android_arm64_v8a

android_x86, android_armv7

The release notes say this:
On Android, we now added support for multi ABI builds, allowing you to
compile your application for multiple target architectures
in one go. We also added support for the new AAB package format, which
allows deploying of a single package covering all target
architectures in one go to the Google Play Store.