I got 'App not installed as package appears to be invalid' message when trying to install my signed release app manually on Android 12. However, it can be installed in my other phones which are Android 9 and Android 6.
I use jarsigner to sign my apk :
$ jarsigner -verbose -sigalg SHA256withRSA -digestalg SHA-256 -keystore my-release-key.keystore <app-release-unsigned.apk's path> alias_name
And use zipalign to optimize :
$ zipalign -v 4 <path-to-same-apk-file> HelloWorld.apk
I've change my phone setting so that able to install unknown apk and tested with app-debug.apk and it works just fine. For more information, my app is written by using quasar framework and built by using cordova.