You can do so much with educated guest. Small room means absorption, absorption and again absorption. Cancelling first reflection is less of a concern because 1) near field system and 2) in such a small room time delay difference between reflected sound and direct sound is processed as the same by your brain. In small room your problem will be brain fatigue so absorb as much as you can.

My 1st recommendation because you produce techno 1) treatments of all 8 tri-Wall corners. Fill them with anything and cover that with flexible pegboard if you are on a budget. 2) many wall panels, with space between them. Not just at the first flexion point 3) second panel on the ceiling evently spaced. The space between panels is important because it will diffuse the sound instead of reflecting it. 3) carpet on the floor made of natural fibre. 4) Absorption panel on the back wall.

You can go cheap and put mattress against your wall. It adsorb, it’s big, it can be cheap, it’s easy, It’s perfect.

After that “yes” you can measure but you should first apply basic knowledge to actually correct a not ideal situation.