I’m having the exact same problem as described by OP.
Uninstalling a plugin (whichever way you do it) doesn’t work immediately. It looks like nothing happens. But then when I close and re-open Obsidian it shows the plugin is gone.
It’s not a big deal, but it is clearly a bug.
Edit: My Obsidian folder is being backed up to Google Drive as well. I’m not streaming the folder from Google drive, the folder is primarily on my hard drive, but I’m backing it up to Google Drive automatically.