Really nice post, easy to understand even for a backend dev. Is the CRP metrics in dev tools or did you use an extension?
Someone just pointed out to me that Google's Lighthouse actually does give you critical metrics, along with a tonne of other useful optimisation stuff. It is actually more geared towards progressive web apps but useful nonetheless for what you're asking about.
Thanks Francois! CRP is a way to help you understand what is affecting your page rendering and how to optimise it. I don't think it appears in DevTools but there may be an extension out there.