Hi, BlackMac,
Welcome to one of the best-kept secrets on the Internet.
Your post takes me back KM 5 or 6 years ago when I first bought KM.
It's like that line from Will Smith's Summertime... "But back then I didn't really know what it was" 

It took me a long time to learn it, mostly because I was intimidated by it"s capabilities. This coming from a guy who works in the Enterprise IT space for over 25 years in hardware and software development.
What I came to realize is that I didn't really have a need or use case that would have made me use it. For me, it started with the Karabiner app that I used to replace the Caps Lock function and use it as a Hyper Key (⌃⌥⇧⌘)
Once that happened, I began to understand the sublime experience that KM is.
With regard to the UI, whenever you start using something new, you're always a tad bit more sensitive to the new thing because you're used to the experience of other apps.
Yes, the UI is old school, but it doesn't consume a ton of compute resources on modern Macs and is backwards compatible with the 2012 cheese grater Mac Pro that is still running today.
We focus on the here and now, but the developers have to take the wider context into their decisions.
My personal view is that i don't care about the UI any more. it works once you get familiar with it. id much rather have the function than the form any day.
Speaking of getting familiar, there are some great, inexpensive educational resources that will help you get up to speed and get more out of KM.
I'm not affiliated with any of these folks, but I am currently or have been a paying customer for all of them.
Screencasts Online KM part 1
Do a search for Keyboard Maestro on that site and you'll get a few more videos to help widen the view regarding what's possible. yes, some of the videos are old, but the content is still relevant because the UI is largely unchanged.
A more current video-based course comes from David Sparks, one of the hosts on the Mac Power Users podcast. It's called the Keyboard Maestro Field Guide and costs 49 bucks.
With those two resources, I went from zero to hero.
With KM, KMLink (a separate software app), a 32-button Stream Deck, and some Z-Wave remote control outlets, I can turn on my home office video setup on and off at the press of a single button. That setup consists of:
- 3 monitors
- a camera
- three Elgato key lights
- two strings of led curtain lights,
- an ATEM Mini Pro video switcher
For Extra Credit:
- it also turns off the aquarium pump so the sound of rushing water isn't heard during calls
- sets my mini-split heat pump fan to low so others won't hear it.
Imagine trying to set all this manually Every. Single. Time. you have a Zoom, Teams, or Webex call.
It did happen overnight, but I'm very happy that I stuck with it.
This community is fantastic. We're all here to learn and help each other out. If you're stuck or come up with a use case that you're not sure of definitely reach out (hint: use the search function because there's a lot of content in here!
,
&
,
--Shawn