The best disk usage UI I ever saw was this one: https://www.trishtech.com/2013/10/scanner-display-hard-disk-... The inner circle is the top level directories, and each ring outwards is one level deeper in the directory heirarchy. You would mouse over large subdirectories to see what they were, or double click to drilldown into a subdirectory. Download it and try it - it is quite spectacularly useful on Windows (although I'm not sure how well it handles Terabyte size drives - I haven't used Windows for a long time).
Hard to do a circular graph in a terminal...
It is very similar to a flame graph? Perhaps look at how flame graphs are drawn by other terminal performance tools.