If you didn't use a password in that wallet, your seed will be readily available to you to copy and restore the wallet, look for this part in your wallet file:
"keystore": {
"seed": xxxx xxxxxxx xxxxxxxxx xxxxxxxxxx xxxxxx xxxx..........
Of course this only would work if you didn't use a password when saving that file.
wallet encryption back in 2016 (if i am not mistaken) was not the whole wallet file so if OP opens a wallet file that was created that long ago with notepad he should still see the JSON file (if the wallet was any version above 2.0) and only see the seed and private keys encrypted in case he placed a password on it. in which case it will be much easier to work on decrypting that since the encryption Electrum uses is known.