Save Modern sites as template, yes we can but should we?

NO.

Saving Modern sites (while do-able) is not supported.

The first hint that it's not supported is the fact that the link "Save This Site As Template" is missing. And as history shows us, if it's missing , it's missing for a reason: It's not supported to save the site as template. Think about Publishing sites, Communication sites, etc.

https://support.office.com/en-us/article/create-and-use-site-templates-60371b0f-00e0-4c49-a844-34759ebdd989

(Expand Resolve Common problems and scroll down to the section "The Save site template command is not available" )

And the what other types of sites do not support save as template , see here for the sites that have publishing features enabled by default ( and therefore not save-able as template)

https://support.office.com/en-us/article/about-publishing-enabled-site-templates-b4fa3dcd-f4cc-4820-aa73-fed106965725

Now, Modern sites: somewhat not obvious but here it is :

https://docs.microsoft.com/en-us/sharepoint/dev/solution-guidance/modern-experience-customizations-customize-sites

Shortening bolding and coloring the relevant parts:

What's not supported on "modern" team sites:

  • Custom master pages; more extensive branding will be supported later using alternative options.
  • Changing "modern" site to use "classic" seattle.master or oslo.master.
  • Custom page layouts; we are looking to have support for multiple canvases in the future.
  • Enabling site or site collection scoped publishing features; technically, features can be currently activated, but this is not a supported configuration.
  • User custom actions / custom JavaScript; there will be a more controlled way to embed JavaScript on the pages through SharePoint Framework Extensions.
  • "Modern" subsites; subsites created on "modern" team sites use the "classic" experience, but you can change the user experience to be similar to "modern" sites.
  • Ability to control available subsite template options.
  • "Classic" publishing features (WCM).
  • Activation of community feature or creation of community subsites under "modern" team site.
  • Saving site as a template. Also not supported for sub sites in site collections which root site is a group associated team site or communication site.