[Vuejs]-Tinymce5 – How to add an external toolbar for classic editor?

Our recommendation to achieve this functionality, generally, is to use the editor(s) in inline mode, and use the fixed_tool_bar_container option:
https://www.tiny.cloud/docs/configure/editor-appearance/#fixed_toolbar_container

Using this option would render the toolbar in the same location regardless of which editor instance was clicked into.

Caveats with this method are that the toolbar doesn’t render until an editor is clicked, and the toolbar disappears when clicking out of an editor.

Here is a Tiny Fiddle demo:
http://fiddle.tinymce.com/Mphaab