Hi guys, is it possible to see how decentralised elrond is? I mean, how much AWS is used?

The choice of Server is up to the individual node runner/ staking provider, nodes are located all over the world, some in people's homes, some using large Servers such as Amazon, but anyone that cares about their node will have a fallback in a totally different location in case of an outage, some have several. I couldn't give you extra numbers of who uses what though, not sure if it's available, but you can ask in @elrondvalidators