I think I finally found a page that explicitly said, "no, graphframes cannot handle different types of vertices," which seems to defeat like 90% of why you would want to use a graph database/only be relevant to the most simple graph database problems.

They blamed dataframes for being so restrictive as a reason for the limitation, but, like, they chose to make this based on dataframes.

It's like group theory when I need cosets rings and ideals. I'd be ashamed publicly releasing this as and parading it as a viable product.