I do believe the biggest impact would come from regulating large companies and billionaires, but it’s not one or the other.
Eat less or no meat probably. Enough people drive down meat demand would eventually lead to cattle reduction and less land for grazing.
Don’t forget about diary.
Edit: *dairy
You’ll take cheese and 2% cow milk from my cold dead hands.
You: “you’ll take cheese and 2% cow milk from my cold dead hands.”
Nature: “hold my beer.”
I mean, this is the problem. We all will be cold and dead soon if we don’t fix this.
Please stop listening to corporate propaganda on this subject. You have absolutely no personal responsibility to solve this problem. The idea that you have to is an invention from business. A way to make it a personal responsibility and not something businesses have to solve.
If no person does anything nothing changes.
Of course your own choices in isolation don’t change much. But that’s like saying voting doesn’t do anything because a single vote doesn’t matter. We all can make choices that add up through all of society.