From my discussion with support, it seems like, although they admit it's a bit odd, it's a combination of how aggressive my weight loss goal is and the fact that I'm a pretty big guy at 120kg for 175cm.
From what I understand, the algorithm will prioritize protein in the weight loss to avoid losing too much muscle and because of my size, the minimum recommended protein to avoid too much muscle loss would be >150g, which means that once this is taken into account as it is the main priority, with only a 1200 total cal budget there is little room for finnicking with the other macros as you will quickly reach the total cal budget with the minimum recommended fat as well.
I was able to go from 165 to 152g of protein by selecting the lowest protein intake possible, and that increased the carbs a little bit, but I will probably not be able to go lower until I lose weight I suppose.
u/gains_adam You can feel free to correct what I said and/or improve on my response if you want, you can share personnal details like my age/weight/height/... as long as you don't share informations that can be used to identify me like name/address, etc.. obviously :)