Network optimization is mostly about reducing distance, round trips, and packet loss. The first question is simple: where are your users, and where is your origin server?
Use a CDN for static assets when traffic is global. For dynamic endpoints, keep redirects short, reuse connections, and avoid unnecessary cross-region calls during page load.
Latency and bandwidth are different problems. A large download may need throughput tuning, while an interactive page usually suffers more from high round-trip time.
Use regional checks to compare real user paths. If only one region is slow, routing, peering, or CDN placement may matter more than application code.