@Fitik
2 possible paths forward:
+ Dokuwiki with some plugins for templates and lists and tables. On a web server.
+ Org-mode and Org-roam (a looot more than Notion). Local.
Maybe TidlyWiki, but I don't know it personally.
How much do you need real-time collaboration?
:)
@Fitik
Then both mentioned options could work. They are different in the balance between simplicity (#dokuwiki is easier) and power (#org-mode has #emacs behind).
Both have huge ecosystems, great documentation, vibrant communities and are rock solid. Dokuwiki is accessible on a website (in the net or in your machine) and org-mode mostly on your machine but it is super easy to replicate or export for use in many devices.
I"ll happily expand if you choose any of those, :)