Stop the whataboutism please. I am Greek, I was in Greece during the 1990s, and you know very well that Greece supported Serbia a lot during the 1990s. Greece tried to stop the wars in the Balkans. I know very well what your politicians and your media were telling you in the 1990s. Some nationalist Greek politicians were telling the Greeks the same things. During the 1990s, I thought that Serbia was mostly right on this, it was only much later that I read about the whole thing and I understood that the blame was mostly on Serbia.
I understand that you hate the West, you blame NATO for everything that happened back then. I assure you I understand. And I understand you must be unhappy living in a NATO country. I really believe it would be good for you if you read a couple of books about it to understand what happened in the 1990s from other people's perspectives, not just Serbs. It will always be hard for you to accept that the Serb nationalists are to blame for what happened back then, but still it will help you realise that it is not what you thought. And who knows, perhaps you will be happier living where you live now. You may also understand that the Russians have nothing good for Serbia (or for Greece, or for the Balkans, or for Ukraine). It is better for us all if the are defeated.
And here is an answer to your question: NATO cannot solve all the problems in the world. But NATO can solve some problems in Europe. And it did solve the problem in the Balkans, with minimum bloodshed considering the situation. Before NATO bombed Serbia, there were years and years when the EU (and Greece) tried to help the Serbs understand the situation and negotiate a solution, but the Serbs refused to listen.