Twitter requires a phone number, they just don't require one at sign-up. This is a known pattern they do with every single account - you have to provide a phone

Twitter requires a phone number, they just don't require one at sign-up. This is a known pattern they do with every single account - you have to provide a phone number at some point. If you ever log in with a VPN, they may also require a number to even access your account at all.