(For safety, all links are on Itch.io)
So first there was Lucky Paradox. The author, Stawer, got the solution from one of his Discord's user in response to Joiplay not working very good, before getting simplified without file manager:
New Android Build for Lucky Paradox | Android Master Guide for Lucky Paradox
Then Zimon, author of Champion of Realms, heard about this, and found the complete method by himself (but didn't explained it publicly), then also simplified it:
Android Version Apk + Addons | Android Simplifications
That is almost all info I have as of now. It might need a bit of online search, or trying to contact one or another.