Meanwhile, you are still ignoring his sin in O God, thou knowest my foolishness; and my sins are not hid from thee. There are other verses in the Psalm that do not conform with the entire Psalm, written by David, being all about the Messiah either. You need explicit New Testament references, not Slick interpretations, before trying to use it as a proof text.
It’s not private, but is wide-open to public examination. The fact that you don’t like it doesn’t make it private ... :-) ...