Suppliment feeding is fine as long as they get the chance to eat all day like they were built to eat. You are probably a very good mandarin keeper and your mandarin probably loves you. But many mandarins won't eat pellets or frozen. I am sure you also have plenty of pods in your tank because all those pellets and frozen you are adding feed the pods. I add pellets all the time, my fish don't eat them but I add them just to feed the pods. If you dive with mandarins and follow them in their natural habitat you will see them eating a pod almost continuously. That's the way a mandarin is supposed to eat. We can feed them other things because it is easier for us, but pellets IMO are not the proper diet for a fish like a mandarin or any fish.
The fact that yours is spawning is fantastic, but most won't on that diet.
As I said, he is also eating pods. Pods are in every tank if you want them or not.
But your mandarin certainly loves you.