Acrobat PRO DC toolbar settings: Where are these stored?

Corrupted preferences settings may be restored but As far as macOS it doesn't offer a repair installation option like in MS Windows, so the users may have uninstall and reinstall.

Also, there is no single one-click option to restore settings via GUI. These settings are hidden and you may need to do it via Plist if you know how to. 

If you decide to do this manually, you need the Adobe Acrobat 

Preferences Reference for macOS.

Some users backup this directory path:

• /Users/(username)/Library/Preferences/com.adobe.[Acrobat.Pro or Reader].plist

rename it and save it or  move it out of the original directory to another location, and restart the application.

The preferences folder or directory should recreate itself with the default preferences.

Here's the Acrobat Preferences Reference link:

• Enterprise Toolkit | Macintosh Plist Preferences 

However, if you decide to uninstall and reinstall,  run the Acrobat Cleaner and Repair tool before reinstalling. This will remove old traces of the software and prepare the system for a fresh install.

 Make a backup of all your documents before you decide to execute these procedures.

Here's the link for that tool:

• https://www.adobe.com/devnet-docs/acrobatetk/tools/Labs/cleaner.html