There is this recent-ish paper (DOI: 10.1126/science.aba6630) on why it might be, that plants forego the peak of the solar spectrum. Essentially it boils down

There is this recent-ish paper (DOI: 10.1126/science.aba6630) on why it might be, that plants forego the peak of the solar spectrum. Essentially it boils down to being able to regulate the photochemistry of photosynthesis. If it were centered on the peak of the spectrum there's not a lot of regulation possible by means of shifting the reaction energy levels around. By placing the light absorbing parts of photosynthesis on the slopes of the spectrum, by mere adjustment of the energy levels the reaction undergoes it can shift its activity to parts of the spectrum with more or less light intensity.