This is on macOS, but all of your notes, folders, and attachments are stored within the vault. The (sometimes hidden) .obsidian settings folder is in there as well.
If you backup this folder, TESTVAULT in this case, all of your data will be fine. When reinstalling the Obsidian app on macOS or Windows, this TESTVAULT won’t be touched.
Have a look at these two topics. One person was able to resolve the issue by reinstalling, and another by renaming the .obsidian folder. Renaming .obsidian will reset your settings, but your notes will not be affected.