You'll probably make the biggest impact by working at a hedge fund and use your excess disposable income to lobby for change
True but nobody wants to hear it. Hell of a lot more effective than punishing yourself to reduce global meat consumption by .00000001% . Or just come to terms with the fact that for good or bad you just don't matter and try to live your life without doing unnecessary excessive harm.
Yes it is not effective if you're the only one in the world doing it, but it has always been about convincing others to drastically reduce or stop completely, whether through word of mouth or policy change.
Producing animal products is unsustainable and come with enormous environmental impacts [1][2]. We need both top-down and bottom-up approaches. So it's worthwhile what individuals and companies/governments choose to do. It's not one or the other.
[1] https://ourworldindata.org/environmental-impacts-of-food [2] https://ourworldindata.org/land-use