I found the answer to my question here on Stack Overflow once I found the right search terms. The short answer is yes, you can add a component that has already been instantiated with data to the DI container. However, there are some caveats to consider.

1. The componet must be created, have it's data added then added to the Service Collection before the DI container is built. Once the Service Collection is built it is read only.

2. This constructor must be used when adding to the Service Collection:

   ServiceCollection.AddKeyedSingleton[TService](object ServiceKey, object myComponentInstance);

3. When the Singlketon instance is pulled from the DI container and used, it is NOT automatically disposed of and remains in the DI container until an explict Dispose is called on that instance or the application as a whole is exited.

There are additional details in the answer as described in this Stack Overflow question: AddSingleton<>() vs AddSingleton()