[amorphous]

Searching for work that brings one into the state of flow is good, but I think it is important not to become too obsessed with it. Otherwise, you may fall into the trap of avoiding difficult work. For example, cleaning the house brings me usually flow, but I wouldn't want to make a living doing that (not that there's anything wrong with cleaning, but I don't think I would enjoy that for long).

I believe any work can bring flow; it's just a matter of keeping the challenge at the right level. In your case, instead of ditching frameworks and implementing engine functionality manually, you may need to find work that requires you to learn new skills and grow.