Add macOS Preference Panes to Your Dock For Quick Access | Tips & Tricks
Brett Terpstra, writing for Lifehacker, points out that every preference pane lives in the folder
/System/Library/PreferencePanes/. Browse to the folder, or click Go > Connect to Server in the menu bar and paste the full path.
You'll find the folder, which contains all of the System Preferences panes.
Simply drag one to the right side of the dock, beside your dock folders and the Trash.
You can drag as many panels here as you want! It's not going to save you a ton of time, but if there's something you configure regularly it's well worth taking a minute to set this up.