I am about 75% sure that “It’s all the companies emitting” is an immensely clever astroturfing campaign that preys on people’s desire for their to be a big bad and to not believe that they should suffer even the slightest inconvenience.

It goes both ways. You've heard of the personal carbon footprint, right? Invented by oil companies so environmentalists would call people out for not doing enough, frustrating said targets of environmentalist ire to a point where a lot of people are intentionally polluting more, while also driving people into a sentiment of "I've done enough, now it's everyone else's fault" when they've reduced their own footprint to a minimum.

The only way for change to happen is political. Regulations work, telling people to stop eating meat and walk to work doesn't, because you'll never get more than maybe 1% of people to go along with it. Who wants to restrict themselves when other people don't?

Basically as an individual, the only way your efforts mean anything is if you decide to go for some good old eco-terrorism. But it has to be enough for fossil company CEOs and board members to be legitimately scared to the point nobody wants to run those companies anymore.

Or if you're a dictator selling gas, you can start a war and some of your customers will stop buying from you. That reduces gas consumption for a while until they find new sources, and might make some governments reconsider their foreign fossil fuel dependency.