(Render founder) We've learned a lot from these outages, most of which stemmed from DDoS attacks. We've since built DDoS protection into the fabric of Render: https://render.com/blog/free-ddos-protection.
Specifically related to this AWS outage, Render can already transparently shift your app between AZs, and we're also working on moving services across underlying cloud providers (GCP/AWS and eventually bare metal).