There is a research project called that managed to boot a very old version of Android (Android 9) on jailbroken iPhone 7 and 8 devices. This is not a converter; it completely replaces iOS with Android.

While you may find "online converters" promising a quick fix, these are often . Here is the reality of what "repacking" or "converting" actually entails: The Reality of APK to IPA "Conversion"

Directly converting an APK (Android) to an IPA (iOS) file via an online tool is not possible