Honestly, I wish folks would stop recommending PID as the go-to tool for control design. Like some others have said, it is never the right answer in any non-trivial system. The problem with newcomers blindly incorporating it into their design for quick satisfaction is that they have just done so at the expense of making someone else's job harder down the line. In a system where many things are interconnected or nested, introducing artificial dynamics via feedback in one part often leads to unpredictable and undesired behaviour in another. Then the next junior engineer comes along and thinks the weird behaviour can be solved with more PID loops, repeating the process until you end up with a un-tuneable mess with a precariously narrow operating region.

If you are working in this field, no you don't need a PhD, but for the love of god invest some time into learning more appropriate techniques for the work. Start with learning to work with MIMO systems in state-space, then learn to use LQR (literally a one-liner in MATLAB) and reduced-order observers, then some nonlinear techniques like Lyapunov functions and integrator backstepping for those tricky nested loops. I'm happy to suggest resources for anyone interested.