How to disable 2FA in my Apple ID?

You just need to make sure you have another Trusted Phone number set up on your account. You then have the option to send the code to another number if your Phone is lost or not available. You are also able to get the code from another Trusted Device.

You are not able to turn off two-factor authentication and most services from Apple that you would use require it. The answer is not to turn it off, but to make sure you have an optional method available in case you do lose your device with another Trusted Phone number and/or Trusted Devices.

Two-factor authentication for Apple ID - Apple Support

The relevant portion is here:

If you don't have a trusted device with you:

If you're trying to sign in and don't have a trusted device with you that can display verification codes, you can tap Didn't Get a Code on the sign-in screen and choose to send a code to one of your trusted phone numbers. This text message might include an additional domain validation line that includes the @ symbol, the website name, and your code (for example, @icloud.com #123456 %apple.com). Or you can get a code directly from Settings on a trusted device.

Learn how to get a verification code

Past two weeks enabled, or if enabled when the Apple ID is created, two-factor stays enabled.

Options: enable one or more recovery contacts, or add trusted telephone number(s), or acquire and switch to security keys:

… Set up an account recovery contact - Apple Support

… Add or remove trusted phone numbers on Mac - Apple Support

… About Security Keys for Apple ID - Apple Support

When other means of access to an Apple ID are unavailable:

… How to use account recovery when you can’t reset your Apple ID password - Apple Support

Set up a legacy contact, while you’re at it:

… How to add a Legacy Contact for your Apple ID - Apple Support

If you have had it enabled for more than 2 weeks, or have a new account, it cannot be turned off. It's important to ensure that you have trusted devices and trusted numbers up to date on your account.