I use to play AOE2 back when I was in school but that was just me playing against AI all the time and trying to just use cheat codes to gather resources etc. I never cared about the build orders, early rushes, booming/turtling. Just enjoyed spamming rock on cheat to get 1000 rock and then build infinite amount of castles :)
Now I started playing AOE4 and I'm trying to get good at it. These are just my notes on all sorts of things(build order, scouting, strategies) that matters in any AOE4 game.