Just wanted to share that there’s an ongoing discussion on an app I created specifically for this use case: https://talk.macpowerusers.com/t/rcmd-fastest-app-switcher-to-date
I had exactly the same need, to bring up the Terminal with a single key press, run a command or just check the status of a long running command and then press the same keys again to hide the Terminal.
Same thing with notes (I use NotePlan) for jotting things down fast or check a list of tasks.
rcmd has the Hide action that does just that. e.g. press Right Command - N to bring up notes, press it again to hide it. If Notes isn’t already launched, rcmd will launch it automatically.
I’m guessing you already have this nice workflow specifically adjusted to your needs, but I thought to share just in case you might like the adaptability of rcmd.
With it you don’t need to create a workflow for every app, it dynamically assigns keys based on your most used apps, and is also very easily customizable.