Similar, but declarative. Dagger uses a programming language, Togomak uses a configuration language on steroids.
Just to clarify, Dagger is both declarative and imperative. Yes, you can use multiple programming languages which exposes an imperative API, but your pipeline DAG has to be defined using Dagger's SDKs which is has a declarative form.
Would it make sense to say Dagger is to Pulumi [1], as Terraform is to Togomak?