I think I have a usable app development experience now on my tablet. I basically took my recent Lua Carousel and made a few changes. In Carousel (first clip) you start in the programming environment, each screen runs a separate script, scripts run in the background of the editor, and each screen manages its own canvas. The new setup (second clip) starts in the app, which takes over the entire device until I 'exit' into the programming environment. In the programming environment, screens are now just editors with a shared 'run' button and canvas. Hopefully I can now finish polishing this turd app entirely on the tablet.

That‘s Android, right? You should be able to update LÖVE without uninstalling, and thus without losing data. And if LÖVE has asked for the right permissions, you should be able to access shared storage.

Perhaps the issue is that I'm installing from a raw apk. Open source project doesn't want to go through app store review.

That's what F-Droid is for. But yes, it has its own reviews and bureaucracy. As far as I know, there is no way to update an app from a raw APK without uninstalling first.