I do agree with your first statement. Of course that is subject, in biblical terms to acceptance of that Sacrifice and God as your King.
2nd statement: If you believe in Christ, and you state Christianity as your religion, then you must take Him at His word. That word for us: Romans 3:23...
Put simply Atonement means at-one-ment. IE: Being brought back into unity with God. It is really reconciliation. (Word Origin Anglo-Saxon).
Salvation, on the other hand is literally being saved from something. In biblical terms that is from sin. Our own sin.
Whether we like it or not we...