I do not get your question: org-mode offer various ZK-alike implementation like zetteldesk on top of org-roam, in mere storage terms a zettel is a heading, real

I do not get your question: org-mode offer various ZK-alike implementation like zetteldesk on top of org-roam, in mere storage terms a zettel is a heading, real links between them allow to travel between notes. You can capture them in a timeline...