Marknote, KDE's WYSIWYG note-taking application, is finally ready for it's first release. Marknote lets you create rich text notes and easily organise them into notebooks. You can personalise your notebooks by choosing an icon and accent color for each one, making it easy to distinguish between them and keep your notes at your fingertips.
Obsidian is proprietary
Yes, and Obsidian has a Linux installer.
But I can’t afford a diamond pickaxe right now
There’s always Logseq. I’ll stick with emacs org-mode though. Learned how to use it in highschool and loved it since.