Want to restrict a supplier in non-catalog requisition

Summary:

We have a supplier specifically for Punchout requisition process. We want make sure non catalog requisitions were not created for this Punchout supplier (as it will not have all info supplier required and price is not correct).

Content (please ensure you mask any confidential information):

We can probably create Approval Rule to check item source and supplier and reject it. But do we have any other better to handle this.

Version (include the version you are using, if applicable):

25A

Code Snippet (add any code snippets that support your topic, if applicable):