Is it risky to change a store's node

It depends.

Changing the node changes the IP the platform sees. Marketplaces watch for sudden changes, to protect the account. When you switch, stay in the same country and region if you can, so timezone and language don't jump. Those two fields follow the node; see How unique device fingerprints work.

A newly registered store is often under review for the first few months — commonly 3 to 6. Don't change nodes often in that window. After the store is settled, don't switch unless you need to.

Which country to buy: Which country should I buy a node in. To add the new node, see Add a node.