There is one way to stop 2fa as far as I know, is by contacting wallet support where you tell them that you have lost access to 2fa and they do some questions including information from your account to know that you are the actual account holder, such as the amount of assets you have in your wallet and also the date of the last deposit or withdrawal and such Things, if you pass the questions successfully they will deactivate your 2fa so you can activate it again.
I don't think that's how it work with their private key wallets because that would be against what they claim:
We cannot (and dont want to): view your balance, view your address book, make transactions on your behalf, confiscate your wallet, or lock you into our service.
Some platforms are less strict about 2fa as they only ask for an email or phone number to verify.
This is the case with them, see:
https://support.blockchain.com/hc/en-us/articles/360000286426-How-do-I-disable-two-step-verification-2FA-