It looks like AR1252 is listed everywhere as AEP-GIG but for some reason it's been going out of EZE this month. It was departing from AEP in the past few months according to FlightAware and FlightRadar24 maps for past flights.

There's another MDZ-AEP flight that leaves at 6:00 and arrives at 7:40; if you can pair that one with AR1252 and are willing to wake up so early, that leaves 3:45 hrs to wait at AEP or transfer to EZE depending on what happens with AR1252 that day. You should be fine with that time unless the MDZ-AEP leg has a massive delay but anyway if that happens Aerolineas should take responsibility and switch you to a later EZE-GIG flight. I don't know Buenos Aires traffic patterns but, if the current Google Maps traffic display is right, morning heavy traffic should be going from the suburbs to downtown and you'd be going the other way.