The given link in this post by @Taifun have the solution of your problem.
This topic only tells to convert apk to aab and sign apk non-thing else.
There are alot of guides available in community for signing apk , aab , apk to aab , play app signing etc.
This topic is misleading the users. Builder already have target the android 11 and mostly people are here for android 12 support.
Can you explain these : -
Why we need to edit the AndroidManifest.xml for android 12 ?
Just changing the number is enough? then builder should jump to Android 12 directly.
most of things is copied from video (which is removed). As far i know the real owner is @AppHelper_Studio
.