This topic has been covered before on the old Reddit site and is indeed due to API changes. Nothing wrong with the game at all and it works fine on Android 13. Just Google screwing with people. Much like Micro$oft forcing people to stop using DOS.

https://www.reddit.com/r/PixelDungeon/comments/15owmbi/vanilla_pd_taken_off_the_ios_app_store/

Thanks to this wonderful thing called a search engine it doesn’t take much effort to find the original PD homepage from where the game can be downloaded for free.

https://watabou.itch.io/pixel-dungeon

https://github.com/watabou/pixel-dungeon/releases

https://apkcombo.com/pixel-dungeon/com.watabou.pixeldungeon/

This might or might of be the case with the original PD, but I recall Google removed a number of apps from the store that failed to keep up with targeting a minimum Android API version number. Could be thwt dev didn’t respond to the alerts from Play Store and the app got removed as part of that purge. I think that happened about the time you mentioned in your post.

I could convince myself there was some discussion about it on the pixeldungeon sub over at the Old Place, but honestly I never played the original version anymore and didn’t really pay attention.

Of course I could also be totally mistaken, so don’t quote me on any of that