For small projects/teams, things like Heroku and Fly.io seem to work great.
For enormous teams staffed with DevOps engineers, AWS and GCP offer an enormous suite of low level tools to build with.
What is happening in the middle ground here? Maybe for teams of 30 to 200 engineers, where you need to deploy multiple services/apps, manage APIs, s2s discovery and communication, etc but don't have dedicated DevOps teams?