Kotlin MVVM firestore callbackFlow: Stuck with IMPLICIT TYPE CASTING to ANY?

I am new to mobile development and I have been following advices from Alex Mamo's lecture and so far it has proven to be working. Now as I am trying to implement new things and fetch data, from one solution to another there are differences that seem to be incompatible.

I have Firebase Auth on this app and now I am trying to go and fetch data from Firestore and I get an IMPLICIT TYPE CASTING to ANY?

Here is what I am trying to achieve:

override fun getBudgetsFromFireStore() = callbackFlow {
    val snapListener = db.collection(COLLECTION_NAME).orderBy("name").whereIn("id", listOf("I91xw6MUBpofeCmYYUCz"))
        .addSnapshotListener { snap, e ->
        val res = if (snap != null) {
            val budgets = snap.toObjects(SettingBudget::class.java)
            Success(budgets)
        }else {
            Error(e?.message ?: e.toString())
        }
        trySend(res).isSuccess
    }
    awaitClose {
        snapListener.remove()
    }

}

and here is the content of my Response sealed class:

sealed class Response<out T> {
object Loading: Response<Nothing>()

data class Success<out T>(
    val data: T?
): Response<T>()

data class Failure(
    val e: Exception
): Response<Nothing>()

so basically, I see that my T? is what forces the cast to ANY, but I can't seem to shake it off. I also have Firebase Auth flow that uses it, so I can't really play with it without messing things up!

Can anyone give me advice, on what option(s) could be available to me in that situation?