What kind of business do you run? Can you explain a bit about how your systems in different providers are connected?
Ignoring tweaks for international customers, each proxy is in an A record round-robin with health checks via Route 53. US-based requests get forwarded to one of the pods, and the proxy either handles the request with local servers, or points to servers in another pod if it has servers that are down. If any pod has a power outage or goes down for any reason, Route 53 automatically pulls the entire pod out of the rotation. If an entire provider goes dark, all of the pods get pulled out of the rotation, but all the others keep running.