Looks good. I think I'm starting to like the Clean Architecture pattern. Your use of Use Cases has inspired me. Also, the project is well organized.
I have some suggestions:
1. You can use the new Koin constructor DSL to make your dependency registration much cleaner.
2. Look into using the environment object from Ktor to get your environment variables. It uses HOCON or Yaml. Using this strategy also allows you to set default values for your environment variables outside your code.
All the best... 👍🏾