How to turn off two factor authentication?

You can’t.

(Sorry for the “harsh-sounding” reality)

What makes you think that you need to do so?

So … since you’re going to have to “live with it” …

Recommend that you carefully review and thoroughly digest the two fairly important and informative articles linked below.

Pay particularly close attention to thoughtfully selecting and setting up Trusted Numbers … these become critical when you need to regain access to your account (e.g. lost, damaged, or stolen device).

Two-factor authentication for Apple ID - Apple Support

and

Get a verification code and sign in with two-factor authentication - Apple Support