Phone number 2FA isn’t useless, insomuch as it’s better than no 2FA at all, but it is easily the worst form of 2FA because SIM jacking (usually involves a scammer tricking a customer service agent into migrating your phone number to their device instead of yours in order to intercept the 2FA messages) is laughably simple using easily acquired info such as your DOB, address, and last 4 of your SSN.
If phone 2FA is the only option, use it. But don’t use it if you have any other option.