The treemap screenshot doesn't look correct. Nearly all charting libs (like Apache Echarts) will group nodes with a heading name, so not sure why they claim it would be hard to notice the "drivers" node. I guess in that screenshot, sure, but that looks like just a bad implementation of a treemap. Maybe this was the case back in 2017?

Flame graphs I have a love/hate relationship with. The hierarchy is very useful, but the name and coloring can be very confusing and misleading. Most people I show them to think red == something bad, but the color is actually just for aesthetics.

At an old startup attempt we once created a nested hierarchy metrics visualization chart that I later ended up calling Bookshelf Charts, as some of the boxes filled with with smaller boxes looked like a bookshelf (if you tilted your head 90 degrees). Something between FlameGraphs and Treemaps. We also picked “random” colors for aesthetics, but it was interactive enough so you could choose a heat map color for the plotted boxes (where red == bad).

The source code got lost ages ago, but here are some screenshots of bookshelf graphs applied to SQL plan node level execution metrics:

https://tanelpoder.com/posts/sql-plan-flamegraph-loop-row-co...