I want to clear some things up

Here baek would have easily won Reasons: it's obvious that a rank difference is a huge jump in power but even between ranks there are levels to this for example A ranks Before the red gate baruka>igris>sung>kim Aftert the red gate baruka>=sung> igris >kim This happens because sung jinwoo's shadows only level up at have the pace of sung's

When we get back to the point multiple of the same low ranks do not necessarily mean they're able to beat a higher rank example in season 1 when jinwoo was fighting the armored soldiers which were b rank level while him being low A rank(which way lower than the state he is now) this could also have been true in the red gate if Baruka didn't waste time and had just blitzed jinwoo since he was way faster.

You also have to consider the fact about jinwoos fatigue level and his mana so even if he was able to summon his shadows they would have a hard time regenerating

So all things considered> baek wouldn't even need to transform to one shot jinwoo his partial transformation would've been overkill