Hey @Andrexl , take a read here:
Bottom line: you need to get a fan that will completely exchange the air in there so the heat doesn’t build up the way it is currently.
As an example, I needed to vent outdoors or the air extracted from my tent heats up the room to a point of diminishing returns where the air outside the tent is as warm as the inside so venting does nothing after a point. This is for my 4x4.
My 2x2 has a inline fan removing all air and has forced air in; this exhaust though just goes back into the room because the heat doesn’t build up.
Edit: the fan you posted looks to be about the size I have in my 2x2x3 propagation tent; and in that example it’s NOT enough for the lights I’m using in there so I leave the door open. 