@DUZULEK Sorry you're dealing with this. Since you've already completely uninstalled and reinstalled Opera, I would first check whether Sync is actually restoring your data or whether the browser is having trouble accessing its local profile.
If you can still access your Opera account, check whether your bookmarks are available through Opera Sync on another device where you're signed in. Also, avoid resetting Sync or deleting any more profile data until you've confirmed that your bookmarks are backed up. If you previously exported your bookmarks as an HTML file, you can import them again through the bookmarks manager.
One thing worth checking is whether you're signed in to the same Opera account you used before. If you are, but your bookmarks and passwords still aren't appearing, it may be a Sync issue rather than something that another reinstall will fix.
Hopefully, your bookmarks are still associated with your account or available in a backup. Have you checked whether your bookmarks appear on another synced device?