I am just wondering if the 2fa would automatically be switched off if someone used the seed phrase because then it would not really matter, when you have the seed phrase all the security no longer matters
The 2fa is only on your blockchain.com account which means if someone sweeps/import your seed using a compatible wallet like electrum, they don't need the 2fa anymore. Also, worth nothing that your 2fa should remain intact even if the hacked used this method to drain your funds. This is why I think the perp had to disable your 2fa to access your wallet which means they didn't have your seed at that time.