To paraphrase my father, the navy man, I run my Mac like a tight and clean ship. Nothing unnecessary is needed or allowed.
I only have one third-party utility running on my Mac: Keyboard Maestro. I do use TweetShot to tweet, but once I do my daily tweets, I quit out of it.
Because of the above, my Mac is never slow. I haven't seen a spinning beach ball in years.
Example: my mouse has drivers that are not the best—they would occasionally cause a conflict. My mouse has onboard memory. A long time ago, I set the mouse buttons up, then I quit the drivers—never to open them, unless I decide to reconfigure a button. And the mouse works flawlessly now—no conflicts or beach balls. Pure bliss!
My hope is that Stream Deck does not need an app (windowless or otherwise) to function as button triggers for Keyboard Maestro. Since Keyboard Maestro recognizes the buttons as native USB triggers, the only thing I believe I would need software for would be to set up the icons for the buttons. I know that there is a python script to do that, and was wondering if there were more options (as I know nothing of Python).
May I ask a favor? Can you quit the Stream Deck app, and see if the Stream Deck is functional at all?