Why not a second account?
A second Telegram account is not anonymous enough for most people. Telegram shows a name on every direct message, and any @username links back to an account. A burner still shows a profile that recipients can screenshot. An anonymous link from Anon Inbox has no profile attached at all.
An anonymous link has no profile to attach. The link holds a random code, not your account id. And Block cuts off an abusive sender at once, with no notice to them.