Is it possible somehow to also show the blank nodes in the visual graph?
I noticed that in the visualization config queries there is a filter using isIRI(...) which makes sure that by default only IRIs are visualized. However removing that filter does not help at all - blank nodes are still not visible, which is a major limitation on the ability to visually expand/navigate the graph.
Even if blank nodes are not useful identifiers, they are necessary to navigate the graph and it's not always feasible to convert them to IRIs.
Visual graph shows only IRIs with their local name or label. Bnodes by themselves are not meaningful.
But you can construct with SPARQL IRIs from your BNodes' data (using the IRI function to create IRI from whatever string you like). These are virtual nodes that do not exist actually, but exist for visualization.
Customizing visual graphs with your own queries is described here:
https://graphdb.ontotext.com/documentation/9.9/free/devhub/custom-graph-views.html