In my case I started writing stories of automated farming communes, compiled my writing in to a zine about a better world, had 260 copies printed and handed them all out, got my then dream job at Google X robotics, then ended up handing a copy of the zine to a robotics engineer and philanthropist who now funds my open source work as we push towards continuous crowd funding as our long term model.
Your story will go differently (lol) but what I can say is that defining your vision, building the appropriate skills, and telling everyone that you can what you’d like to do probably helps a lot. You may have to stick with the unfulfilling job for now, but you can try to build an exit strategy.