Queen’s gambit was solid? I thought it was equal between solid and offensive. 3min? you can’t learn anything or can’t get used to calculation and can’t get used to seeing tactics, weaknesses, pawn structure or anything of that sort so I recommend 5/2 if you want something that goes fast and you can learn stuff, but you won’t be able to learn too much so 10min, 10/5, or 15/10 for improvement. Note that the longer time control means more learning, but if you have other stuff to do lower is also good.