" don’t need Kubernetes nor serverless."

Actually 'serverless' is where small shops might want to start.

A single Lambda can encompass a whole variety of functions, and if you're using a datastore that scales as well, you don't need to worry about much. Once it's set up, it should be very easy to monitor and change.

I'd rather a simple Lambda than managing a couple of EC2's with failover scenarios and the front end networking pieces for that.