I perfectly understand your desire for more customization options in Asana (I’m also this type of person).
Currently, what comes to my mind in terms of customization:
the colors of custom fields (when definig the color of each option) - those fields will also give colors to your timeline and calendar views (“Color” option on the top right)
the colors of diagrams and charts
the project icon (and color)
I think that Asana has limited color and background customization for the time being, due to concerns about design consistency and accessibility. However, it is mentioned that there are customization options under development.
But one of the best workaround to make your projects alive is the use of emojis.
You will find great articles :