>I wouldn't describe my current work as mundane, for better or for worse. To be successful here long term I'd need to spend a greater percentage of my mental cycles on work than I've been able to muster so far. Not necessarily working long hours, but definitely have work projects be the thing my mind falls back to when I'm in the shower, if that makes sense.

You might want to reflect on this - how are you evaluating "percentage of mental cycles on work?" Are you comparing it to other people in your team? Are you comparing it to a person who gets "extra outstanding" on their employee review or "good worker, happy they are here" on their employee review? I ask because it's possible to be a good employee, do good work, and get to the point where you can and do this without needing to think about work in the shower. Usually it takes 3-6 months at a job before you figure out how you can find that balance.

Is your perception about your commitment to your work skewed because you had 100% control before and you think that's how things need to be for you to be satisfied at a 9-5 job?

Also, IMO if you are thinking about your job in the shower you are not thinking about your side projects, something you are learning for fun, etc. It's hard to be focused on life outside of your job if you are thinking about your job outside of your job. A lot of people who think about their job in the shower do so because of misery and stress, not because they care about the work they do.

>I've thought about looking for a job as a line of business app developer in a mid-sized non-tech company.

Please think carefully about this. If you're the type of person who needs to care about your work, it's soul crushing to be in a job where you can't possibly care about your work. I've had "I don't care" types of jobs before where I did 2 hours of real work in a day. Those jobs are tolerable for a while if your manager leaves you alone for those other 6 hours. I had one of these, and I had the choice of asking my manager for more work (resulting in 6 hours of pointless busywork) or making it look like 2 hours of work took me 8 hours. In either scenario, I ended up going home frustrated and it was very difficult to change to a mode where I could be productive with life outside of work. I thought about work in the shower because I was miserable at work, and a shower meant another day was coming where I had to go to work.

Also, part of being inspired as an entrepreneur is being in an environment where you can be inspired. Many of these jobs are not that place.

> I'm worried that this might be me. I try to imagine myself being happy even at a small startup with lots of autonomy, and I suspect that even in those circumstances I'd have a hard time feeling motivated to work hard to make somebody else rich. :(

If it's you, don't worry about it - embrace it and figure out a way to make it work. :) It's better to realize you're an entrepreneur who is trying to find their way as an entrepreneur rather than being an entrepreneur who wishes they were somebody else. Or the other side, there are people who really are 9-5 people who refuse to admit this and constantly dream about being entrepreneurs.

You might not be able to figure out how to be an entrepreneur today, but that's okay.