We are using QuickApps 5.7 for SharePoint Enterprise. We created a project management template for subsites. Each subsite created from the template has task list. We want to rollup tasks on a page on the parent site. So far, so good. We have over 30 task lists to rollup. Our creation is automated addition to the lists to view. So when a new subsite is created the resulting list is automatically rolled up to the webpart.