Can I add two phone numbers for 2 step authentication in case one of them gets damaged

Yes you can and it is a good idea to do so. See the section titled About Trusted Phone Numbers and Trusted Devices in this Apple support article.

Two-factor authentication for Apple ID - Apple Support

You should get a code on the new number for verification purposes. After that, if both phone numbers are used by your Apple ID as trusted devices, then the code will go to both. Otherwise, the code will go to the phone that you are signed into with your Apple ID.

I have 4 trusted devices that all get a code when I have to sign in with 2FA. My wife’s iPhone is also listed in my Apple ID to get a code. She would only get the code of my devices are not with me.

From the related article above…

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.