While it is true that reversing combustion would require more energy than was released burning it, I don't think anyone reasonable is proposing it. The proposal is to redirect future energy production away from fossil extraction and into cleaner sources (solar, wind, nuclear, geothermal) which is a completely different thermodynamic problem. The constraints are things like grid storage capacity, permitting timelines, and critical mineral supply chains - not physics.

If we overcome these very real contraints, we reduce the rate of new additions to atmospheric CO2. We will still need to do the thermodynamically hard work of removing CO2 at gigaton scale, but deferring that until removal tech is more mature is the right sequencing.

Of course, this assumes that we are actually working towards the CO2 output reductions right now and really committed to CO2 removal in the near future.