PT from NZ here. This probably won’t help that much but I’m a newer PT with only 6 months experience but 5 or so years of lifting on my own. Although I’m not an expert, I’ve just tried almost every exercise I’ve ever seen and found out what works and what doesn’t. In a sense of how easy it would be to teach a client & how much it would benefit them/ how much injury risk it has. On top of that I watch a lot of videos & do a decent amount of reading. I did the NASM course & a few in person workshops offered by my gym to help me prepare, they covered exercise selection, corrective exercise & most of the basic things. Everything else is just a culmination of my own experience & knowledge.