"Super Mario Bros. Wii 2: The Next Levels" Does Not Exist

No such game exists. You may be thinking of:

• New Super Mario Bros. U (2013, Wii U) – Direct sequel to New Super Mario Bros. Wii.
• New Super Mario Bros. U Deluxe (2019, Switch) – Port with all DLC, extra characters.

These are the closest official follow-ups.