Those launch/focus app hotkeys in Karabiner are exactly why I made rcmd (https://lowtechguys.com/rcmd https://lowtechguys.com/rcmd) I had a similar setup first

Those launch/focus app hotkeys in Karabiner are exactly why I made rcmd (https://lowtechguys.com/rcmd https://lowtechguys.com/rcmd) I had a similar setup first in Karabiner, then in BetterTouchTool for easier configurability. But I needed the system to be smarter about this and allow me to assign keys on a whim, not have to change a config file. rcmd automatically detects your most used apps from those already running and assigns keys to them. It uses the Right Command key as the trigger, but it’s completely configurable to any other trigger like the mentioned Control+Shift in the post. It also allows you to hide/show the app fast (I do that a lot with the kitty terminal) or cycle between apps with the same first letter.