I'm familiar with lean methodology and aware that ideas don't really mean much, but at the same time I'd like to work on some big problem that's compelling. I know that I'll probably pivot a lot but just to start out what general problem would you reccomend I try and solve?
Your skill set is a good one. It's in high demand and your ability to do the work will open doors for you. In the short term your problem is not, "ideation" however. It's the appearance of being pompous and overly complex. Fix that and things will start to fall into place for you.
Coding freaks out most business people. They don't get it. They don't know C++ from Zip+4. But they understand their needs and they can often communicate them with reasonable clarity. If you're using buzz words like, "ideation" when you're talking about something as simple as developing a concept - you're advertising that you'll be difficult to work with if only because you're hard to understand and possibly have a tendency to travel with the herd instead of blazing your own trail. If your English usage is difficult to follow, they'll assume your technical documentation will be incomprehensible. That's not the message you're trying to convey.
Instead, try this. Speak English. Simple English that a high school student could understand. If you're truly gifted and innovative that talent will come shining through. Your choice to speak and write in language that is easy to read, easy to understand, and easy to pass along to others will make you a sought after consultant, contractor, or business developer simply because you're a pleasure to work with and can get the job done. Those are key skills. Knowing and using the latest buzz words on the other hand will never impress anyone you need to impress. It may even keep some of your best possible clients from taking you seriously - killing opportunity before you even get the chance to really show them what you've got.