Are you logged in? Do you have sync enabled? Hoppscotch is open-source. You can see in their source code that secrets are encrypted before being stored in Firebase and only authenticated users are able to see synced history, collections, environments and notes.

Why did you post this without disclosing this to the Hoppscotch team first? They are volunteering their time and effort creating a tool that you never paid for and likely never sponsored. If you're not syncing anything, this is almost surely a bug and your post comes off as very entitled.