Kiah_Evergreen It shouldn't matter that your game is installed on a different drive than the EA App. Many of us have that same setup.
The "game data missing or damaged" error is common and has its own master thread:
[CURRENT ISSUE] Sims 4 Unable to Start, Game Data Missing or Damaged | EA Forums - 11819181
If you can launch the game but are getting this error, try the other suggestions in the first post rather than worrying about the repair. If none of them help, or you're stuck in a repair loop, we can focus on that part instead. And in that case, try clearing the EA App's cache and starting another repair.
https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/