I will say this:
It's good that you were introduced to the simpler built-in apps. Hopefully that does take a lot of complexity out of the things you want to do. --And there's a lot of power in those, too, as it pertains to being mode-aware and such.
Regarding the "pretty terrible" UI of Rule Machine:
I will agree that it was ANYTHING but intuitive when I started. --Especially with the specific quirks in HE about clicking out of a box after you make a selection, which locks that selection in and opens up the next step, etc. I had no clue what I was doing with the UI. No clue. "Insert before" and stuff...it took a while. And there's an argument to be made that intuitive is objectively good.
HOWEVER: I just want to say that, with time, and with more use--not even study and practice, but just normal use--the interface becomes very second nature, and it doesn't even seem weird anymore. I had some experience with WebCORE before coming to HE, and while I'll admit it was a little more intuitive for a beginner, and seemed more powerful (because you could see everything at your fingertips, instead of features becoming available based on context and where you were in the process), it no longer feels superior in any way. I think about automations in "Rule Machine" ways, and it's very easy to deal with now.
Good luck! --And if they want to come up with an easier-to-learn flow, I'll be happy to see it as a refinement of this platform. Win-win