The laws of thermodynamics still apply. To reverse the process of making CO2, you must expend a lot of energy. More energy than you produced burning the carbon.
The carbon we burn today was stored sunlight from photosynthesis in a forest or a swamp full of green slime algae. (or if you're a fan of 'abiotic' carbon, it was ??? energy left over from planet formation) ... but it's silly to think it makes sense to reverse the process and turn CO2 back into hydrocarbons on an industrial scale. If you have a nuke plant, do something useful with it like powering a steel mill. Sequestering carbon is a fool's errand.

We already have ways to sequester carbon, they are called trees.

Meanwhile, here is some science for you to trust:
https://youchu.be/8jDqUcnBotk?list=PLGhmZX2NKiNldpyRUBBEzNoWL0Cso1jip&index=24&t=2334
What are we going to do about all those carbon-wasting viruses?