Is a Page Builder required at all for this Plugin to work?

Absolutely not.

The Toolbar Extras plugin has a lot of features for the Admin Bar that are fully independent from any Page Builder at all. So, of course, you can use it even if you have no Page Builder in use, or even none of the other supported plugins or themes activated.

Toolbar Extras only loads features for third-party products if those are installed and activated and otherwise goes gracefully out of the way.