No, that’s not what I’m talking about, but yes, you should likely delete ALL of those duplicate Obsidian apps. (Obsidian 2, Obsidian 3, etc.) Why do you have so many? Are you aware of which one is running when you open Obsidian? This might be the source of your problem. Fix this first. Delete them all, and then reinstall. This might fix it without having to delete your app settings.
I assume you are just running the wrong one, and it’s an older one.
The .dmg files are just the installers. You can delete them too. But that isn’t the issue.
To get to your app settings, go to Finder, and hit Cmd-Shift-G for “Go” and enter the path there. Please be careful in this settings folder. I take it you are not highly experienced with MacOS yet? (Which is fine, just be careful.)