💯 unfortunately if the app you used doesn't let you export your nsec, you can be locked out. You can however keep making accounts elsewhere
Discussion
You're not using #nostr if that is the case, just like you're not using #bitcoin if all you have is a Binance account.
😎👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻
Another problem is some clients like Amethyst only let you export your nsec but not the mnemonic words and some tools like Alby's browser extension only let's you import mnemonic words but not your nsec.