How do i bypass Activation Lock on a second-hand iPhone X?

You most likely bought a stolen phone.

Activation lock is a security protocol that can't be bypassed. Only the person it is locked to can unlock it.

If you bought this from someone and it came locked, try to get your money back, you will never be able to use the phone.

The All Too Common SAD Reality of Buying a used phone -

https://discussions.apple.com/docs/DOC-250001038

Nothing. It’s a brick. Return it and get your money back or toss it in the recycle bin and take this as a life lesson.