PDS (Power Distribution System) design is an art and science on par with Signal Integrity. For non-trivial designs, they both require a deep understanding of the real-world technologies involved as well as a detailed iterative process to arrive at a solid design...and you can never achieve perfection.

Real components, every component, including the PCB, are not anywhere close to what EE's are generally taught in school. The the physics equivalent to starting a problem with "assume a cow is a uniform sphere of mild one meter in diameter".