How does the CDN system give different IPs to users about one domain according to the user’s local DNS?

I was curious about the principle of CDN giving different IPs to users about one domain. The principle is called Request Routing. Using the CNAME record type, go through CND’s Domain Name Server and receive an IP of cache server that was selected based on optimal conditions. So, each user can obtain a different IP despite requesting about the same domain.

Reference from https://www.netmanias.com/ko/post/blog/5630/cdn-dns-http-request-routing/request-routing-technology-in-cdn

• If Local DNS has the IP of origin.example.com, it response immediately (10). Otherwise, the optimal cache server’s IP is obtained through the recursive resolution of (4)~(9).
• The TTL of (6) and (9) are different. (6) is very long, 1~24 hours, and 9 is short, abound 60 seconds. The optimized server taken in step 9 is variable over time because not only the geographic distance, but also various factors such as the health check of the server, the load status of the server and the network environment affect it. Therefore, keep the TTL of step 9 short.

Reference from https://www.netmanias.com/ko/post/blog/5622/dns-data-center-gslb-network-protocol/global-server-load-balancing-for-enterprise-part-2-site-server-selection-policy-1