I second the import Private Key method mentioned by LoyceV. (the wallet is online so make sure that your machine is totally secured)
And I'm particularly curious if they've already fixed the issue of displaying the compressed WIF format of old imported private keys which leads to address mismatch when importing to other wallet.

The steps are simple:

• Export the private key WIF via "Private Key" option.
• Install and verify Electrum: electrum.org/#download | bitcoinelectrum.com/how-to-verify-your-electrum-download
• During wallet creation, select "Import Bitcoin addresses or private keys" and paste your private key.
• Finish creating the wallet, wait for it to sync and send using that wallet with the fee slider set to your preferred sat/vB fee.

Now, if it shows a WIF (Wallet Import Format) private key that starts with "K" or "L" and it didn't restored the correct address after import, the issue is still there.
If that happens, use this method to encode the private key to the correct format: https://bitcointalk.org/index.php?topic=5517924.msg64733265#msg64733265