"Create shareholder value at my current startup" obviously isn't going to scratch that itch in the same way.

I would add a little nuance. One thing is your job isn't advancing Humanity Progress in a very direct and unambiguous way, say you work for some Very Important Organization that Does Good All the Time. Another thing is your job is totally useless or even harmful to society.

Maybe most of us are in between?

I've worked at dysfunctional companies that made me personally unhappy (busyworks, company politics, waste, bad bosses, bad teammates...) that somehow made some good things in the grand scheme of things, other that made me very happy with more neutral results.

Someone has to do mundane things, even to raise children and give a chance to the next generation to improve the world.

I don't believe putting too much thought in purpose is healthy.