Add Metal to an existing app

Hello. I am trying to enable Metal to take advantage of SwiftUI+Shaders in an existing app. In my target, I have added metal.framework, added a .metal file and confirmed I see the Metal Compiler option in my Build Settings. When I add a colorEffect modifier using the ShaderLibrary, the object renders black. I confirmed this is working in a new project so I suspect there are more steps required to get this working in an existing application.