I would like to be able to add a link to a Document that is in a Module I use called DocMan directly from SP Page Builder. I asked the developer at https://www.joomlatools.com/ and here's what he said...basically, I need to ask you.

Thanks for the additional information, this helps a lot. So you just want to insert a link to a document in SP Pagebuilder. This would be more a question for them then for us really.

Let me explain. Joomla offers so called editor and editor-xtd plugins, and internally also an editor plugin API. An editor plugin is the editor itself, for example the core distributed TinyMCE, or third-party JCE.

Extension developers who wish to add additional functionality/buttons would create a so called editor-xtd plugin which can extend any editor, as long as the editor itself implemented the Joomla editor API.

Looking at your picture I'm seeing what looks like TinyMCE/JCE but the custom editor-xtd buttons provided by various plugins are not present. This would indicate the editor is not integrated the editor-xtd API.

Long story short, if SP Pagebuilder integrates the editor Joomla API, the DOCLink button would just show up in the editor, like it does with JCE.

I suggest you forward this question to SP Pagebuilder team and get there feedback.