i’ve tried to use the name of the app, path to the app, activity monitor name of the app, and the app’s PID, but terminal can never find it
The whole reason for this, is that an App, is so much more than an unix executable binary file, so that it is launched in a whole different way, by the launchd daemon, that we usually refer to as launch services, where one of the steps, is to execute a unix binary, that resides in the folder MacOS of the package that are named as Appname.app.
That is why you can just type the name of the app in say Spotlight, and it will open, the sophistication level is so much higher. However, this sophistication level is replicated in the Terminal by the open command.
You should really read the man page of the open command (man open), to see all the stuff it can do.
When you want to open an app from the command line, try this for example: