> Find some specialization/niche you're interested in software wise, and start learning + building in public about it.

This is a very different and mostly non-overlapping skillset compared to focused product engineering at a company. I believe it's a good way to get you there if you have the time and drive to develop those skills. But then if you do are you going to be satisfied with the prize being a job where you don't use them?

I'm not discounting this as effective, I just don't think it can work for very many people for several different reasons.