Ask HN: Diagnosing high load? Why isn't there a tool?

I often find my Macbook Pro (running 10.14.5) has a high load average, despite CPU and memory usage both being low. I try checking disk usage and I have read various suggestions on ServerFault, StackOverflow and elsewhere. I understand the difference between CPU usage and load (I think!).

It drives me crazy that the machine knows load is high, but there is not a simple tool to help me diagnose why.

Anyone got tips on a straightforward but thorough process?

Also, why is there not a script that can be run to check various things and give an answer ("In the sample period, program ABC contributed X.Y to the load average, primarily due to disk IO. Program DEF contributed W.Z due to CPU usage.").

I guess I am still not fully understanding the issue fully, but that makes the question of why there isn't a tool even more pertinent.