I have met both new users to bitcoin and now a new user to Nostr who lost their private key because they didn’t back it up and (for whatever reason) decided to delete the only app where the key was stored because they ran out of space on their phone.

There is no reset button for a private key!

There is absolutely no one who can help you recover it!

Making a backup is easy, it takes less than a minute to do.

I guess mistakes are still the best ways to learn, but please, at least try to learn from someone else’s.