Check the title ID. For LEGO CITY Undercover, the base ID is 0100A3500B6A8000 . The update ID will be similar but with 0800 at the end. Ensure you are not mixing regions (USA/Europe/JPN updates are not cross-compatible).
Here’s a sample article or blog post you could use: LEGO CITY Undercover Switch NSP UPDATE
LEGO CITY Undercover offers a vast open world to explore, complete with a variety of districts, each with its own unique character and challenges. Players can drive a range of vehicles, from sports cars to trucks, and engage in on-foot combat with the Brickster's henchmen. Check the title ID
Version & build