Hello. I have seen many people (mainly early bitcoiners) that own keys in the form of paper wallets.

Most paper wallet generators provide the user with a private key and an address.

For educational purposes I have developed an app in java that generates  paper wallets. I have run it multiple times offline and I have tested it in Bitcoin's testnet. The way I tested it was just sending test money to the address and then recovering the wallet in Electrum, Sparrow and BlueWallet using the private key.

Although I am happy with what I have done, I needed to recover my wallet and be connected to the internet. Before sending REAL money to the generated address, I need to verify I can access it using my private key. But how can I do it in a safe and private way? Preferably offline.