How to configure CNAMES to be part of a WordPress Network

Correct me if I’m wrong, but I believe you are mixing up the terms of CNAMES and subdomains a bit.

In case you are looking for a subdomain setup for WordPress Multisite: Yes this is possible:

The sites in a network have different URLs. You can choose one of two
ways for the URL to specify the site:

-Each site has a different subdomain. For example: site1.example.com, site2.example.com.

-Each site has a different path. For example: example.com/site1, example.com/site2