If not, dumpwallet, then extract the private keys from the wallet dump file,
e.g.: Google search for ways to extract the texts that you need from a text file, but you must only meddle with the dump file in an air-gap machine.
Thanks for the response. Can you please elaborate on this part?
I'm assuming dumpwallet output includes both the addresses and the corresponding private keys
address 1 : private key 1
address 2 : private key 2
...
So I need to extract the private keys from this file and import them into Electrum. Can I import multiple private keys at once in Electrum?