Subpages for Pages in AppStudio

"Currently using tabs for this, but client has big desire for mobile, and some tabs don't make sense to have in mobile but you can't disable tabs in mobile only pages.
Ideally I would actually love for tabs to be treated as pages (both would obviously be best for flexibility) but things like importing dashboards would be great if they could be imported to a tab and not just a separate page" - ID

Having sub-pages similar to how we have sub-pages for Pages/Dashboards in AppStudio would be a great feature add and allow more flexibility in navigation and organization of Apps.