Figma or Miro makes it quick to get started, rather than making your own structure from the scratch.
Part of it can be figured out by Goodnotes team such as todos or calendars, maybe more for the power users such as SCAMPER or customer journey. The rest of it can be left upto the community to be figured out on their own.

It is essential for the Templates to be accessible in-app. Search and download. Having favorite templates marked down for quick access in every category, maybe have some AI magic in place to change the color theme real quick.