The way to think about things with booleans is definitely a learning process. It’s similar in how you unite and subtract vectors in Illustrator or Figma just in 3D with bevels arrays and mirrors in the mix.
I’ve found that I often keep blender open during the day to just noodle about in. With regular or Fluent modeling. Even as I went to sleep last night I was trying to figure out how to make a vent cover in my head so I can try it again today.