Revit 2021!?!?!?!?!?!
I don’t have that installed and can’t get it. Hopefully you’re not working in something that old, but you certainly shouldn’t be doing something so schematic in a model in that build.
I updated the model to 2025 and built this sample graph that uses modern techniques instead of stuff like cycling lists. Give it a shot at rebuilding on your own. Note that you may want to adjust the family type sort as well as filter some (to allow for manual placement).
