There is already an opensource alternative to Obsidian, its name is #Logseq, you have mobile and desktop app

I really hope so, it should be taught, because for me it was a slow learning process. First I started using Obsidian, and moving all my notes from Evernote, Notion, and others manually. After that I moved to Logseq, which is like Obsidian but open-source. And the last step was using an open-source syncing tool (Syncthing) to have my notes synced locally in all devices. And now I have been 2 years self-hosting my notes in a really easy way.

U. t. c. s. stands for: “usese también como sustantivo” which means: “it can be used as a substantive/noun”