That is correct. By overwhelmed, I have meant exactly this, i.e. if the terrestrial plants had captured more solar energy, the only effect would have been the

That is correct. By overwhelmed, I have meant exactly this, i.e. if the terrestrial plants had captured more solar energy, the only effect would have been the accumulation in their cells of free oxygen and of intermediate reduced chemical compounds that could not be used fast enough to synthesize useful substances like carbohydrates, for various reasons, of which the lack of enough captured carbon dioxide is a major reason. The capture of carbon dioxide can be hampered by the free oxygen produced by capturing solar light, even if the plant cells attempt to separate the cell parts where these incompatible processes occur. It might be possible to improve the productivity of the plants by improving their ability to capture carbon dioxide, more than by improving their ability to capture light. However I believe that such research directions are misguided. We are already able to capture light very efficiently with non-biological devices and the same is likely to become true for carbon dioxide capture and electrolytic reduction. What is unlikely to happen any time soon is to find any way for synthesizing complex organic molecules like those needed for food as efficiently as by using living cells. So the non-biological capture of solar energy and capture and reduction of carbon dioxide and dinitrogen should be combined with biological syntheses in cultivated organisms.