@santisbon But the second, more important one, is that permissions are defined at a document-level, not on triples. And you need to make sure that the SPARQL endpoint respects those permissions. So that could be challenging to implement properly.
There has been this discussion about the document model vs the graph model, but for now it's all in theory. The current spec is using a document model. If you're interested, you can learn more about it in this blog post: https://ruben.verborgh.org/blog/2022/12/30/lets-talk-about-pods/