With good hardware, btcrecover will descramble a 12 word BIP39 seed phrase in an hour:
To be clear the "good hardware" in this context for this duration means a 48-core cloud computing server not a regular good hardware PC. With a PC with the best CPU you would get a couple of hours, possibly 5 or 6.
That's for BIP39 mnemonic, but for Electrum it should take a lot less by a factor of about 12.