> joined the industry circa 2013, and discovered that most of the big tech jobs were essentially glorified plumbers

Most tech jobs are glorified plumbers. I've worked in big tech and in small startups, and most of the code everywhere is unglamorous, boring, just needs to be written.

Satisfaction with the job also depends on what you want out of it. I know people who love building big data pipelines, and people who love building fancy UIs. Those two groups would find the other's job incredibly tedious.