You’re saying heat is your determining factor, but you have more light coverage than needed. These statements don’t really belong together. You need to run plants under leds hotter generally. Your uv supplementation May bring your leaf temps up to negate that, but I can promise in a 4x4 if you could put another 200 watts in there without affecting your heat, you would yield more in that space. Imo that means not enough light. Again, depends on your goal, but mine is generally to pull as much weight as I can out of a space.
That’s said, if you’re pulling 1300g+ than disregard my statement.