How can I turn off two factor authentication

You can only do it within 2 weeks of turning it on:

https://support.apple.com/en-us/HT204915

If you have used it for more than two weeks, it cannot be turned off. It is an important security feature.

Use two-factor authentication for security on your Mac, iOS devices, and iPadOS devices - Apple Support

You cannot.

How is 2FA stopping you getting a code? 2FA is for when you sign into your AppleID iCloud account on a strange device.

You may be getting confused about why you cannot get a code. Are you talking about Hive’s own 2FA requirement?

PS in UK You don’t get 2 weeks grace. if an AppleID is used to sign into an Apple device then 2FA is permanently set.

I would have expected Hive to send you an SMS - have you checked that?