Best practices for project sheets so data can roll up to portfolio dashboard?

My team manages many projects, each having a sheet with many parent and child tasks. I am researching ways to roll project data up into overall portfolio views for leadership but all of the PPM/PPO templates Smartsheet provides seem to pull portfolio data from an "intake sheet" which is not a process we employ. I'm finding it difficult to produce simple reports showing data by project because of all the parent/child nesting. We are in the middle of revamping our project templates and I want to make sure I design them in a way that will allow us to easily roll up data to a portfolio view (% complete by project, number of overdue tasks by project, all projects owned by a person, etc). What best practices do you all recommend for accomplishing this? I am using a roll-up row at the top of each project sheet and was thinking I'd utilize the Sheet Summary for certain things but would love any guidance you can offer. Thanks!