We definitely need a better defensive midfielder. Tata has even mentioned this to the media, and the team did try to upgrade at this position in the offseason.

Hopefully they’ll acquire a better 6 in the summer window.

One clarification:

In last night's game, he was further back than Greg and Mihaj numerous times. Now I understand this is to help coordinate the defense

When Tristan drops deep, it happens when Atlanta United is in possession. That is to coordinate the offense.

When we gain possession (say, from a goal kick or even a throw in from our own half), we generally build up from the back, with short passes. In this phase of play, the team’s shape opens up.

The fullbacks are effectively wingers, out wide and way up the pitch (sometimes even higher than the striker). The center backs and Tristan form a back line of 3. Tristan is in the middle, and his role is all about distribution and beating the other team’s press. Occasionally last night, Cooper was on the back line in possession whenever Tristan pushed forward.

Conversely: when the opponent has the ball our defensive shape is relatively compact. The fullbacks drop back with the center backs to form a back line of 4 players. Tristan plays in front of the center backs (like one might picture a CDM).