The most mindblowing thing to me is that these firms are such a gigantic economic force, they could for example invest in renewable energy or sustainable industries. They could have our future low-carbon world by the balls, like Shell or ExxonMobil do today.
Insurers and banks could divest from their carbon-intensive assets, but they will lobby and look for every loophole to protect themselves from responsibility, while being pulled feet-first into a meatgrinder.
Electric turbos are amazing and F1 should push for efficiency, as that's way more relevant than "synthetic fuels" imo. Something to consider is that as long as cars are fueled for the whole race, engine efficiency also reduces weight. Per this article
If efficiency drops from 50% to 40% for example, because of the removal of MGU-H, engines will need 25 kg more fuel to deliver the same amount of energy.