What is the deal with Graphical User Interface/app psychology?

Like where is the goto psych/CS UI 101 class/book/YT that over simplifies but grounds someone with no background or previous knowledge? Maybe something like the "Blender Doughnut" of great UI design?

I've changed UI twice with an app recently. I have a slight intuitive grasp of what I don't like, but I lack the language and depth in this niche to express the emotional response well. I have no clue where to start with my own designs if I ever felt motivated to create one.