Yes, it sucks when a loved app is removed without a trace from an appstore.
Sometimes you can find it in another appstore altogether.
Other times, you need to figure out another way.
Because I set up so many decices, I have recently tried a new (to me) method that seems to work great.
Put all the apps onto an SD card in apk format.
When you get a new device, put that SD card in it and install all the apps.
Sometimes there is compatibility issues, but at least you have the name of the app to search for a working version for the new device.
Glad you found APK Extracter.
Not sure if it is the same one that I use.
https://f-droid.org/en/packages/axp.tool.apkextractor/
I just went through and selected what apps I wanted, then moved them to the card.
Another way is to upload the apks to cloud storage, and download them to the new device.
In fact, you can even send the apks directly to the new device if both are on the same Wi-Fi and both have NitroShare.
https://f-droid.org/en/packages/net.nitroshare.android/