1) The hardest tech possible. I want to test my intellectual limits, which was not possible in the corp world.
2) The most hyped areas, today those are AI/Kubernetes.
If you have a unique solution, then it should not be a problem to get early adopters.
Moreover, after leaving my corporate job, I began:
1) Working 17 hours days, 7 days a week.
2) 100% software dev.
To sum up, if you leave the corp, you must increase your focus.