Include Content in SharePoint Custom Site Template

NicolasKheirallah  Well basically I am trying to create a SharePoint Online Custom Site template that users can use as a starting place to create site. We want to include content for library and some link lists. I know there are many ways to create custom site template, PowerShell, PNP, REST API. I am not tied to a method, just trying to figure what which one allows for including site content in the template.