I do not want my Apple Cash balance to pay my Apple Card, how do I change that?

For information on turning off Apple Cash payments to Apple Card, see the following from: How to make Apple Card payments - Apple Support

Turn payments with Apple Cash on or off

If you want to pay from only your bank account without using your Apple Cash balance:

1. Open the Wallet app on your iPhone and tap Apple Card.
2. Tap Pay.
3. Choose a payment amount and tap Pay [amount].
4. Tap your bank account, then turn Apple Cash on or off.
5. Tap the Back button, then authenticate with Face ID, Touch ID, or passcode to make a payment.