Do You Design Your RJ45 Port as a System or Component-by-Component?

I've been researching the RJ45 signal chain (connector → protection → CMC → transformer → PHY), and I'm curious how others approach this:

Do you source all these components from one vendor and use a validated reference design? Or do you mix and match based on individual specs and pricing?

I've found the system-level approach saves significant debug time, especially for EMI and PoE, but I'm interested in real-world experiences from the community.

Full breakdown of the RJ45 ecosystem: https://voohuelectronic-ux.github.io/voohu-rj45-guide/resources/rj45-ecosystem.html