can you exclude Design from your QMS?

YES
Product design can be excluded if you can provide sufficient justification
Process design is not a requirement for ISO 9001 QMS

clause 3.1.2 of ISO/TS 16949:
Design responsible organization
Organization with authority to establish a new, or change an existing product specification
NOTE: This responsibility includes testing and verification of design performance within the customer's specified application.

- see also sanctioned interpretations