I actually gave fly.io a whirl over the weekend. was not fun. spent a lot of time on the forums and its pretty clear it has some way to go before it can give AWS or Linode a run for their money.

For instance, we run kubernetes on multiple VPS providers, including public clouds with serverless onramp/offramps deployed on edge location. Anything under 15 minutes are processed by serverless. Anything longer is offloaded to one of the VPS containers available in every part of the world.

I have some more feedbacks ready if you are interested, its a neat idea but not exactly as seamless and easy as the idea proposed since public clouds already offer a way to do this.