How do people actually learn Brand Strategy & Brand Identity professionally?

I’ve recently gotten really interested in branding and I’m trying to understand how people actually become good at things like brand strategy, positioning, and brand identity design professionally. I’m not talking about just making logos, I mean the full process agencies do for startups and companies. Things like building a brand system, creating positioning, typography, packaging, presentations, and all the thinking behind premium brands. Right now I’m basically starting from scratch and trying to figure o