I like software and computer science, but "software engineering" barely counts as either

There are jobs (e.g. database engine development) where knowledge of distributed systems algorithms comes in handy. Most likely not nearly at the level of your theoretical PhD, but also much more stimulating that adding fields to JSON.

The statement "my options on who will hire me are kind of limited" is a bit misleading. Limited compared to whom? Your options are abundant compared to most people. It sounds like you are waiting on a fantasy position that has both interesting work and pays at least the same as your current position, which you have 13 years of experience in. That's not usually how life works. There are trade-offs. If you want to do a different type of work that you don't have any professional experience in, you are going to have to take a pay cut. As you mentioned, you're fortunate to be making 3x what you need. It's up to you whether it's worth "only" making 2x what you need in order to do work you find more engaging. This is not a unique circumstance. People make this trade-off all the time. Maybe talk to some people who did.

There's no requirement to put qualifications or experience on the CV that aren't necessary for the role. Hiring managers make a lot of assumptions, and if specialisation is going to limit opportunity then leave it out.

Possible other option: I hope to soon go part-time. IE keep my current job with the pay rate, but change the balance of hours worked. And if it doesn't work how I like, go back to full time. I like the idea of studying physical design... but we'll see how that pans out.

> I like software and computer science, but "software engineering" barely counts as either. I expected to be utilizing a million data structures or figuring out proofs of correctness or designing the next amazing distributed system, but it feels like 2/3+ of software engineering is "add field to JSON" or "write a for loop to convert something to a different shape" or "change color of button" or "change width of page layout and then modify selenium tests", and the only data structures that ever get used are hashmaps and arrays. I spent so much time learning the minutia of CSP and TLA+ and set theory and I feel like I have basically nothing to show for it, and now I can't really even change to a career where I would get to use them. So, around 6-7 years ago I was on a development team and was getting tired of a bunch of things - the frontend treadmill (react/redux, do it this way, no that …

If you are really making 3x what you really need, you should be building wealth at a rapid pace. Once you are financially secure, you can stop doing unfulfilling work just because the pay is good. I 'retired' early because I don't need to work for anyone anymore. My wife and I saved and invested so we are set financially. I still love to program so I spend my time and energy working on a project that is personally fulfilling to me even though it has yet to bring in meaningful revenues. BTW: it is a new data management system that is designed to be a distributed system. Have you considered teaming up with someone on a side project?

I guess you’re in USA. Luckily I am in poor Germany with way lower salaries. Which opens me another option 6) go into trades. Becoming certified electrician takes a lot of time or money or both. My university degree with an expensive course was enough. Salary stays the same as long as I am self employed. Otherwise 5) since 4) does not really work for me. Helped too many brilliant guys as an electrical engineer. Products got traction, but nothing big happened.

This is your chance to decide what your values in life are. Money or fulfillment. Maybe you can alter the software job somehow to make it more fulfilling to you. An organization with a purpose or mission that you believe in. A role with different type of expectations or work. Maybe writing on the side or starting a family.