Adjust your expectations. You are not turning your Jelly Bean phone into a 2024 flagship; you are making it usable .

Most apps (YouTube, WhatsApp, Netflix) now require Android 6.0+. The Store may look empty because it filters out apps your device can't run.

Ironically, the Play Store will try to update itself to a modern version (which will crash). To stop this:

If nothing works, perform a factory reset (backup first) and immediately install the Play Store APK before any other updates.