@ton Did you also have a look at Zettlr? It is also open source software using Markdown file and has great integration with Zotero.
@ton I remember having seen comments in the Obsidian forums about people combining both tools. As for the network graph, when trying out Roam Research it was the feature I was most interested in, but after a while I found that I never used it.
@jeroensangers
I have been using Obsidian on my Mac and, in parallel, using Nextcloud Notes to edit and view the same Markdown files.