Shameless plug..
This is exactly what we do at MNX Solutions. We are a team of Linux engineers, and provide 24x7 monitoring and response to outages for your cloud based infrastructure.
https://www.mnxsolutions.com/it-services/managed-aws-cloud
Even if we're not a good fit, I'd be happy to chat with anyone about ways to improve their site reliability. It's something we're good at, and love to talk about!