Unfortunately, uninstalling Opus will delete the configuration as well as the program. (Something we'll be making optional when we replace the current installer/uninstaller in the future.)
If you have a recent backup of your PC then you'll be able to get the config back from here:
If you have a backup, copying that folder out of the backup, with Opus fully exited (via File / Exit Directory Opus) and then re-launching Opus will be enough to restore the config.
Alternatively, if any config backups had been manually created via Settings > Backup & Restore, then those can be restored via the same menu.
But if there isn't a PC backup (or at least C:\ drive or user profile backup) nor a manually-created one then the settings may be lost, I'm afraid.