If a campaign objective is 'website conversions' and the bidding strategy is 'target cost', what data input is absolutely required for X's algorithm to function correctly?

If the campaign objective is 'website conversions' and the bidding strategy is 'target cost', conversion tracking data, specifically a properly configured X Pixel or Conversions API, is absolutely required for X's algorithm to function correctly. 'Website conversions' means you want users who click your X ad to complete a specific action on your ....