How do you imagine “provide those first of all as NuGet packages using dependency injection”? DI basics say that component declares its dependency needs (best practice tend to be by constructor) and application during the boot up composes the components with needed dependencies (composition root).
I see our current code as an antithesis of DI and I would prefer to spend energy on complete overhaul of the base code to enable DI instead of trying to build a “clean” code on top of it.
What I mean indeed is that the service adapter would declare its dependencies in the constructor. So e.g. it would require Configuration. In this case it would be a .net core dependency. It could also require something like IRuleEngine (which we do not have) and that would be provided by us as an independent nuget package (not a part of Origam.Service.Core).
What I am describing is not an overhaul of all our code, just a way how to provide dependencies to the workflow services.