I was not required back when I registered on twitter.

And yes I do have some burner phone numbers too if I need one but I generally just dont use services that need it.

I don't think I ever gave twitter my phone number. Was that ever a requirement or is that just in case you need to reset your password?

It is not a requirement but if you don't provide it your account gets suspended as soon as you tweet. This happened to me multiple times.