If I buy a i-phone SE but never activate and use it, Why does Apple still control it?

I bought the phone during Covid, it was too small. So I went and got my 12 pro max . Now I try to sell it to someone who wants it, it can’t be cleared because it’s under my old Apple ID . I can’t remember the password so I have a 400.00 paperweight. ( if we still used paper) why is it so hard to prove our selves to Apple? Why is my name not M…..F…… anymore?