Ability to add custom workdoc templates into a new workdoc

When creating a new workdoc, there is the ability to insert some pre-designed workdoc templates either via the ‘quick starters’ selections, or via the +add button > more options > Templates > select pre-designed template.
I would like the option to either edit those existing pre-designed templates, or to add new custom workdoc templates to the list selection.
For example, we have a recurring weekly meeting with a specific agenda, and therefore a custom workdoc template for the outline of the meeting. We want to keep a running workdoc of our recurring weekly meeting notes, but we have to copy/paste the template into the workdoc vs being able to insert it into the workdoc via the +add button.