6 nights in Puebla/CDMX

Hi all, going to be in Mexico for a couple of weeks next month and just trying to figure out the last leg of the trip.

Myself and my partner will be flying to Puebla on the evening of the 14th of June and our flight home from Mexico City is on the night of the 20th.

We'd like to spend a bit of time in Puebla so we'll stay there as well, but we can't decide how best to split the time. 2 Nights in Puebla seems a bit light considering we arrive in the evening as well. However, if we spend 3 nights there, that naturally means only 3 nights in Mexico City, including the day we leave.

Is this enough or are we not doing CDMX enough justice and we should spend longer there? As in, should we be spending 4 nights there at a minimum?

Keen to hear what people think because we are really struggling to decide.. What would people choose here or has anyone any other related advice about this?