So the real question. What do we do next? What do we do once we've done it. Coding in Rails and Elixir is only a challenge when I get irked, but it's not a real mystery.
Where do we go? Where have you gone? Once you get there.
Or start new projects for your own curiosity. I implemented a cache policy recently and I learned -tried- to develop different parts of an OS.
I mean the side project thing is nice, but I've done that to death. My github repos are full of android and Iphone games, at least half a dozen rails projects. Some elixir.
Just job's wise. I hate having a "job" and that's where I"m at right now. I go to "work" every day.
The reality is you only need to become competent with the tool (code), thereafter you are better off achieving excellence in how you apply it (business domain), which will typically require some non-tech specialisation.
Just find an industry niche where you care about what you're coding for, it doesn't have to be some grand cause, just what grabs your interest.
Go to grad school?
Lisp?
Electrical Engineering?
Management?
What do you want to do?
Good luck.