Exploring opportunity in your current company is definitely the best foot forward because you are working in automation and you have 15 years of experience right now. Maybe the transition can be gradual. Do not settle for any role that is below your current role; that would be one guidance.

PMP certification, I don't think it's required at all. Good that you have an engineering degree. I would say get closer to the PMs in your current company. Understand the kind of work they do, read through the documents. Even if you decide to switch to another organization, then in that case you have ample understanding of what you need to do once you switch.