I'll try that at some point; however, I don't believe that's ever resolved the problem when the error has been that the "package is invalid." It does tend to work when the error is that the package conflicts with another package, but if the package is invalid, it's just as invalid for installs as for updates. Not my first rodeo....
If you can't install either [Android version] then try what I suggested in the initial post, where I posted the update. Make a backup of your saves, delete your current version and then install the epilogue. I'm not on my usual setup so my renpy is... Scuffed, to say the least. Updating the .apk might not work until I have my stuff back.
I'm well aware that you aren't on your typical set-up and can't do anything about this for the immediately foreseeable future (and of course still hope that that situation is resolved sooner than later, for your own sake!). If I give it a try, I'll let you know what happens; I'm a bit leery of destroying an install that has stuff I haven't played yet (I've held off playing for at least a couple of updates).
FYI - several developers have been splitting Ren'Py Android games in two for installing larger games. There's a basic launcher, and a separate Ren'Py archive file with the entire contents of the game itself. The installer is the .apk, and is tiny. The user then has to move the archive file to the proper location (requires a file manager that lets you get access to some locations users might not normally see; I use X-Plore). Pale Carnations and A House in the Rift are both using this now.