Planned economy isn't mandatory for socialism. Market socialism exists, for example the socialist market economy practiced (quite successfully) by China. (And no, I do mean democratic socialism, not Social Democracy or the Nordic model)
I think anyone can point to USSR and China as examples of failed planned economies, so I am quite surprised by you claiming to know nothing about that. I wouldn't include Cuba because there have been a lot of unjust outside pressures against its economy. I will say I don't know much about the AES states so I will have to look into that, but at a quick glance I don't see anyone describing their economy as planned?
Oh, OK. If that's what you believes... (I wonder if you have talked with someone who actually live in China currently?) I don't think there will be much more I can say that would convince you otherwise. But I do recommend you to read broadly and try to consciously combat your own confirmation biases.