The change in the address format might be due to the wallet using a different address format, like legacy or SegWit.
Your funds should still be accessible with the private key. Try importing it into a wallet that supports the legacy address format to access your Bitcoin.
Please check the first post again. acme89 already emptied the wallet two years ago and moved the coins elsewhere via Blockchain.com. Hence, there are no more bitcoin to access on the old wallet. He just wanted to practice importing private keys into UniSat and was surprised when he noticed a different address compared to the one he funded years ago.