C4C ATP calculation to block sales order

Greetings to all. I hope all is safe and doing well.

I want to block a sales order and prevent to be sent to the ERP if a position has no stock, or the ATP is not calculated.

I am trying to use work flow rules but the ATP Quantity does not have the operator to compare with null or not assigned values, the same happen with the ATP date.

Is there a way to achieve what I am trying to do?

Best regards

Gustavo Arias