Basic hotkeys are modal, somehow (Open Help from sidebar. Try to use Cmd-W to close). No interface tabbing support (this app is likely an a11y fire). No proxy icons. The menu bar is supremely basic – and they don't capitalize their own app's name ("About obsidian"). The command palette calls Finder the "system explorer." Somehow no print support, anywhere. Custom context menus abound.
Best one: close the main Obsidian window on macOS and try to figure out how to reopen it. (Reopening the app is one... there's one other way!)