can’t fix this warning: TextToSpeechService.cs(60,56,60,63): warning CS8603: Possible null reference return.

C#
public void Speak(string text)
{
if (_tts != null)
{
_tts.Speak(text, QueueMode.Flush, null, null);
}
}

public new void Dispose()
{
    if (_tts != null)
    {
        _tts.Stop();
        _tts.Shutdown();
        _tts.Dispose();
        _tts = null;
    }
    base.Dispose();
}

// Explicit interface implementation for IJavaPeerable
void IJavaPeerable.DisposeUnlessReferenced() { }
void IJavaPeerable.Finalized() { }
JniManagedPeerStates IJavaPeerable.JniManagedPeerState => JniManagedPeerStates.None;
JniObjectReference IJavaPeerable.PeerReference => new JniObjectReference(Handle);
int IJavaPeerable.JniIdentityHashCode => Handle.GetHashCode();
JniPeerMembers IJavaPeerable.JniPeerMembers => default;
void IJavaPeerable.SetJniIdentityHashCode(int value) { }
void IJavaPeerable.SetJniManagedPeerState(JniManagedPeerStates value) { }
void IJavaPeerable.SetPeerReference(JniObjectReference reference) { }

// Implementation for IJavaObject.Handle
public new IntPtr Handle
{
    get
    {
        return _tts?.Handle ?? IntPtr.Zero;
    }
}

}

//attempt 2 Implementation for IJavaObject.Handle
public new IntPtr Handle
{
get
{
// Use null-forgiving operator to assert non-null return
return (_tts?.Handle ?? IntPtr.Zero)!;
}
}

//attempt 3 Implementation for IJavaObject.Handle
public new IntPtr Handle
{
get
{
if (_tts == null)
return IntPtr.Zero;

            return _tts.Handle;
        }
    }

//attempt 4
public new IntPtr Handle => _tts == null ? IntPtr.Zero : _tts.Handle;

//attempt 5 Implementation for IJavaObject.Handle
public new IntPtr Handle => _tts != null ? _tts.Handle : IntPtr.Zero;