MacOS – There’s a folder shortcut on the dock, next to the trash. Why is there and how to remove it

You could use an Automator service or one of the global-keybaord-trigger apps to run a script that switches between two different Dock preference plist files and then relaunches the Dock.

#!/bin/sh
#you'd have a dock-work.plist and dock-home.plist file 

cd ~/Library/Preferences/

if [ -e dock-is-work.state ] ; then 
    rm dock-is-work.state
    touch dock-is-home.state

    #save changes to existing Dock setup
    cp com.apple.dock.plist com.apple.dock-work.plist

    #copy home setup to main preference location
    cp com.apple.dock-home.plist com.apple.dock.plist
else
    rm dock-is-home.state
    touch dock-is-work.state

    #save changes to existing Dock setup
    cp com.apple.dock.plist com.apple.dock-home.plist

    #copy work setup to main preference location
    cp com.apple.dock-work.plist com.apple.dock.plist
fi

osascript -e "tell application \"Dock\" to quit"

_{(I haven't done bash if-then-else in awhile, so this might not execute as is.)}

For any app you want to add to your dock as a shortcut, the process is as follows:

1. Launch the application. The application's icon will appear in the dock.
2. Right click the application's icon in the dock.
3. Go to "Options".
4. Select "Keep in Dock".

Now the application's icon will remain in the dock as a shortcut when you quit the application.