No need to be scared. This issue is just a case of the app failing to display, and I’m guessing it’s triggered by some fiddly thing we’re doing with workspaces or CSS or something.
Either way, though, thanks to Obsidian’s your-files-are-yours principles, your notes are perfectly safe. In the worst case described above, deleting .obsidian would mean losing which panes you have open and the settings of your vault. But I don’t even think that should be necessary to reset the app; a reinstall will probably work.
Beyond that, all other markdown editors (and plain text editors) will be able to view and edit your notes if you ever run into trouble. Keeping one you like around as an “operational backup” is not a bad idea!