When you say "'a la carte' consultancy", do you mean with a one-shot payment?
Do you think that the "user-friendly" features (deployment monitoring/rollback, CI on all branches, health monitoring...), that you can't have with Terraform only, are useful enough to ask for a recurring one?
People will pay you to build out their cloud infrastructure one feature at a time, or pick features off the cart as they want them (so maybe like an all you can eat cloud buffet?). There's a bonus to that too, iterative consulting is a great way to validate a tech stack for a problem domain before you figure out how to turn it into a recurring revenue source.
AWS for all its flaws is actually pretty good for this already, which I think is why it gets so popular with seed stage startups before they get locked in (plus the credits that they give out like candy...). I don't have to think about architecture, I google what aws cli command I need to set stuff up and move on with my life.
It's exactly what we've started to do: targeting startups in incubators.
DevOps people in early-stage startups are not very common, so it's seems safe to say that a Devops-as-a-service may be useful for them.