I can't tell much about your infrastructure, but memcached would probably increase that by several orders of magnitude. The NGINX module is pretty simple: https://nginx.org/en/docs/http/ngx_http_memcached_module.htm...

Cloudflare with Cache-Control headers is even simpler if you're okay with adding Cloudflare as a dependency.

From an ASN lookup, it appears you're hosting on Oracle Cloud, so Cloudflare would also give you free data egress: https://blogs.oracle.com/cloud-infrastructure/why-cdn-client...

Their Always-On feature would also help if Oracle has an outage.

I like the general idea, very lightweight and more likely to remain accessible when an emergency is overloading the mobile networks.