or you could just seperate the rpa file from the apk and have people manually install it like everyone else does now to get around it, as long as the game's save location is not in the data folder(usually in documents). Joiplay is clunky and janky and there tends to be way more bugs directly caused by joiplay. I've also seen people build the apk as an installer that downloads the game without the need to build the game itself into an apk.
what do you mean by that? Like devs? Or players? Cuz it's as simple as uploading the apk and rpa file in an archive with a "Readme" that says to place the rpa in the "game" folder. If anything it's more complicated to learn how to use joiplay than just drag and drop files. At the expense of only a bit more work for the devs of course.