So the issue seems to be the nature of the work ("I did not find the work challenging or interesting, I felt like a cog in a well-oiled machine and easily repla

So the issue seems to be the nature of the work ("I did not find the work challenging or interesting, I felt like a cog in a well-oiled machine and easily replaceable"). A simple solution: start your own small business. Write an app or a web service and sell it to people. The work will be as challenging and interesting as you want and you'll be the ultimate decider. A supreme leader of your own organization. Note: by "simple" I don't mean "easy". I'm doing exactly that, I'm working on a project that I hope will become an income generating business (https://presstige.io https://presstige.io, for full transparency) but it's risky and requires lots of work. Also consider than your ennui is more about how you look at things than objective reality. Many people would be deliriously happy with a stable, safe, well paying job writing code and I'm sure many people are quite happy doing exactly that.