Well as you’ve seen some will quibble over the semantics of who to who, but in short and quite SIMPLY as Paul states, and I can think of no other way… “God was in Christ reconciling the world to himself”, period. And as I’ve noted elsewhere… Paul’s following imploring is SIMPLY the invitation if you will to step fully into the blessedness of that reality, which is where the likes of repentance and faith come into play.
Let me put it another way… those ascribed as being “in Adam” did NOTHING to be so placed in him, i.e., they didn’t need to acknowledge, confession nor believe in Adam — it was a unilateral imposition. Likewise, those ascribed as being “in Christ” did NOTHING to be so placed in him — such placement ON BEHALF OF ALL was the sole work of the Father and Son alone.
Repentance and faith are matters of responding to the call of God in terms of service to Him… that’s a different matter. However, the UNILATERAL work of reconciliation to where God in his amazing grace CHOSE to no longer hold to man’s charge that which stood over and against him, i.e., their trespasses, is what Paul speaks of in this passage.
I’m ok if you’re not buying this deal Dave, but it is the stark difference between my position (pantelism) and that of universalism… to me it is uncomplicated without any attempt at explaining away supposed difficult verses — it’s NOT difficult IMO, but that’s me.