My launcher setup might be interesting, I use KISS launcher but as an "Assist app" and a traditional launcher as my "Home app." So the majority of my time I am using Launcher3 from AOSP, it's not quite abandoned by Google for their two other proprietary launchers but it is just the bare minimum. But when I want to quickly open something by name I hold the home button, KISS launches and I start typing the app name.
This has been possible via shortcuts in custom ROMs for along time, but it has also been possible in AOSP since 5.x at least.
Android 7.x
Settings > Apps > Cog > Assist & voice input > Assist app
6.x
Settings > Apps > Cog > Default Apps > Assist & voice input > Assist app
5.x
Settings > Apps > Google App (Or current default app) > CLEAR DEFAULTS
Then hold home and select KISS as default
And apparently OnePlus has it under Settings > Buttons.