in those Jewish communities?

China needs to expand to keep growing. With a shrinking population and only dangerous options on their coastline (they're surrounded by vital trade partners from Indonesia to South Korea, so any military aggression is self-defeating), the smart move is to try and economically slice off whatever chunks of resource-rich Siberia they can dominate. Xi already has Putin on a leash, so it's probably unnecessary to try and move the borders. But making eastern Siberia their private mining resource is practically inevitable.

of plentiful fresh water located around there too