Back then, I booked a 2 day Keysight course on AEL and PDK development. That was really worth the money!
And then I just started, my main use is automation for EM simulation as shown here:
https://muehlhaus.com/products/rfic-inductor-toolkit-for-ads
You are right that some commands are not document, or when you record the AEL macro using Tools > Start Recording Macro, they sometimes use equivalent command instead of the documented commands. You need a bit of guessing sometimes.