With keycloak you can have a single local password to all your selfhosted apps: you sign in to keycloak, then you sso into everything else from there. I’m building that out on my homelab right now, and it’s working fine.

Just use Obsidian without using folders, then? They’re completely optional.

Can you clarify what you mean about the folder structure? As far as I know, Obsidian doesn’t change up the directory structure at all; it just uses what’s already there: if you’ve got folders, you’ll see them in Obsidian. If you don’t, all the notes will be in one big directory.