I hope it’s okay that I bump this topic. I would like to second iinfra. I’m starting to build more and more in Rust and there my RAM usage typically stays incredibly low. One production web app that is used internally by about 30 people, with a SQLite database, and running on Render.com peaks at about 0.0003 CPU and 20 MB RAM. I suspect there is a big market for hosting tiny services. I currently host them myself on a $5 VPS with a reverse proxy or Cloudflare serverless when possible, but I expect that Fly.io could do it too.
EDIT: Nevermind, I see Reliability: It's Not Great now. Thanks for sharing that. Hopefully in a few months/years 
That’s okay