The Switch version received significant updates to improve online play stability.
If you are playing offline, ensure your signature patches are up to date to bypass firmware checks.
Install the latest update file (e.g., v1.02 or higher). The system will automatically merge the update with the base game.
Use tools like DBI or Tinfoil to check the integrity of the NSP.
Ensure you have enough space (the base game is approximately 13GB, plus updates).