csv - When importing a CSV file of 3 million data in Neo4j is there any way to create the 3 million ratios quickly?

Question

These are the queries I use to load from .csv file:

USING PERIODIC COMMIT LOAD CSV WITH HEADERS FROM "file:///products.csv" AS row CREATE (:Product {id: row.idProduct, name: row.name, description: row.description, price: row.price, shipping_price: row.shippingPrice});

In this consultation I take days to create relationships:

USING PERIODIC COMMIT
LOAD CSV WITH HEADERS FROM "file:///products.csv" AS row
MATCH (Product:Product {id: row.idProduct})
MATCH (category:Category {id: row.idProductCategory})
MERGE (category)-[:OF_CATEGORY]->(Product);

Is there any way to create, or import relationships for millions of nodes?