Version: Android 11
Context: The app has been de-listed from the Play Store but I have the app installed from an official purchase. I want to move the app to another device.
I found this related thread but it requires rooting and the "AppMonster" app linked in the accepted answer is no longer available. The discussion also pertains to a very old Android version.
Is there a newer method available without rooting? I don't want to void my warranty just yet.
I used the SuperBackup app which I had many moons ago and I remembered it had the ability to backup installed apps as APK.
When I backed up the de-listed app, it said along the lines of "APK saved but has no user data because your device is unrooted". I went ahead anyway and installed the APK on another device and logged in with the same Google Account I purchased it with as previously suggested.
There are plenty of app-based solutions available specialized on this (also some file managers like Amaze mentioned in Robert's comment on your question cover this as well) – or you could simply use adb.
If you're on Linux (Mac or Cygwin should work as well), my tool Adebar has a fitting script in its tools/ directory which can even deal with split APKs, watch out for getapk: when called without parameters it gives you details on its syntax. The script can extract single APKs, or APKs of all system or user-installed apps at once.
Install MiXplorer (https://forum.xda-developers.com/attachments/mixplorer_v6-58-4-api29_b22020920-apk.5532509/) and then follow these steps.
