Android emulator: (Windows 10, 11)
(Purchase the Android version) You can run an Android emulator program in your PC then install Android apps from Play Store. We have users reporting good results with Memu, and BlueStacks; (others with LDPlayer 4 and Nox having no problems either).
(You would install the Google Play Store into the emulator if not already there.)
We have a tutorial but unfortunately we do not offer support when you're running the app with a third party app since we don’t have control over the other party’s app.
Additional Android emulator and BlueStacks information here.
If you have previously purchased iReal Pro from the Play Store, make sure you are signed in to the Google account you used for its previous purchase (inside the emulator) so you can install iReal Pro for free.
Amazon AppStore: if you have purchased from Amazon, you should be able to install the Amazon AppStore app into your emulator, then install your Amazon android purchased apps. Download from Amazon here.
Slow or older PCs will probably not run emulation software well.
Windows 11:
Starting March 6, 2024, Amazon Appstore is no longer be available for download from the Microsoft Store on Windows 11 devices. After March 5, 2025, Amazon Appstore on Windows 11 and any apps downloaded from it will not be supported.

The Amazon Appstore and the Google Play Store are separate companies, they do not transfer app purchases between each other.