> It's the first time I hear about graph-relational DBs.

This is unsurprising, because we just invented the term :-)

> Is a graph-relational database something completely disjointed from a graph database?

Graph-relational is still relational, i.e. it's a relational model with extensions that make modeling and querying graph-like data easier. And in apps everything is graph-like (hence GraphQL etc). An important point is that graph-relational, like relational is storage-agnostic, i.e. it makes no assumptions on how data is actually arranged on disk.

Pure graph databases, on the other hand, encode the assumption that data is actually _physically_ organized as a graph into their model and query languages.

I guess the word "graph" is simply too overloaded in computing.