"Energy balance" isn't the right diagnosis because the energy balance has not changed significantly: the sun is and has forever been the dominant energy source in climate terms.
Broad-spectrum sunlight hits the earth, and is later emitted as infrared. CO2 is transparent to UV, but absorbs infrared. So global warming is a consequence of the fact that the major fossil fuel emission is opaque to a wavelength of light emitted by the sunlit earth.
"Letting less enter", "stored the excess energy", and "reflected some fraction" are all huge engineering solutions to the global warming crisis. And I support them all! But space mirrors and geo-scale energy sinks are sci-fi, they will not save us any time soon.
Reducing consumption buys time. Switching to renewables buys time too. Maybe you use renewable biofuels and capture the CO2 emissions: now your car is carbon negative, without launching a space mirror!