Secondly, it's extremely unlikely that research in academia aimed at getting a PhD will be suited to being turned into a business. The purposes of "research for degree" and "research for product" are totally different. If you try to achieve one by doing the other you'll likely succeed at neither.
To answer the question you started with, the problems you work on in getting a degree are ones agreed between you and your supervisor during your preliminary work. For a PhD you need something sufficiently mainstream as not to be dismissed as a toy problem, obscure enough that no one else is likely to be working on it, hard enough that results are worth the degree, and easy enough that you can make progress in a severely limited time. As I say, finding a problem that suits those criteria and then also asking that it's research that can be turned into a product is all a bit much.
There are avenues to explore other than taking a PhD. Spare time projects, contributing to Open Source, reduce your hours at BigCo and start a consultancy on the side, go freelance.
A PhD is probably not the best option, but in the end all I can do is provide an opinion for you to take as grist to the mill.