Hi jacob. Thanks for your time to give the detailed reply. While I do understand the issue regarding using 2020. owner/client does not want to upgrade the version, as other discipline model are in Revit 2020,too.
I will try your suggestion about spiting surface.
Also, I am attaching the dynamo graph and revit sample file containing the roof element.
Samply-Roof-Fordynamo.rvt (4.9 MB)
Create Mass from Element surface.dyn (26.8 KB)