What or symptom are you seeing? (Black screen, missing cars, crash on boot?) Which installer are you using? (DBI, Tinfoil, Goldleaf?)
For everything to work correctly, you must follow a specific order:
This wasn't just a race. It was a breakout.
Complete Guide to Gear.Club Unlimited 2 on Nintendo Switch: Making NSP, Updates, and DLC Work
This tool allows you to combine the base game, update, and all DLC into a single consolidated NSP.