I was also using Karabiner to launch/switch apps instantly but I got tired of editing large configs to add/remap keys to apps. Eventually I wrote rcmd (https:/

I was also using Karabiner to launch/switch apps instantly but I got tired of editing large configs to add/remap keys to apps. Eventually I wrote rcmd (https://lowtechguys.com/rcmd https://lowtechguys.com/rcmd) to streamline this workflow of switching/launching an app by the first letter of its name. It will dynamically map Right Command + first letter of app name to already running apps, and you can map your own letters by just pressing Right Command + Right Option + letter to assign. I eventually replaced everything I was using Karabiner for with specialized apps like rcmd, HyperKey (https://hyperkey.app/ https://hyperkey.app/) and skhd (https://github.com/koekeishiya/skhd https://github.com/koekeishiya/skhd). I'm still missing the left/right Shift press once for parentheses, but I can live without it.