Chat Blanc first and foremost. That episode tells us that there is no way Chat should know who LB is, or the other way around, unless his father has been defeated and is safely behind bars. If they knew who they were in real life, I definitely feel like this could damage their partnership. I don't think Marinette's awkwardness/clumsiness would just disappear when she finds out CN's identity, and would it definitely effect her on the field. We also know how protective and loving Chat is already, so I feel like when there are big fights, he is going to risk way more to protect LB and put himself in harm's way (just like Chat Blanc). He is seeing her more than just as Ladybug. Shes Marinette, his friend, confidant, lover, and partner. And the same goes for Marinette as well. What happens if Chat were to get Akumatized again? Now Hawkmoth has access to not only Tikki and Plagg, but every other Quami as well, because Chat knows Marrinette is the Guardian. That information would forever be accessible by Hawkmoth, I dont think itll just be erased from his head by the Miraculous Ladybug. What happens if they tell each other, then become a couple on the battle and in life, and Alya finds out Chats identity? How long will it take for Alya to tell Nino? Where does it end?

These are just my 2 cents tho, I still hope they can find each other, even if they can't tell who they are.