Yup I agree with you almost entirely. The only thing I was thinking of was if evolution would optimize for the amount of energy a plant receives vs other things like survival, reproduction etc and how much efficiency we can gain by optimizing purely for photosynthesis.

Also I don’t know if plants are adapted to the high CO2 atmosphere yet so even if evolution optimized the ability of a plant to photosynthesize, given this happened in relatively low CO2 environments like forests and without man made climate change, it’s possible that human intervention can improve it.