As these are downloadable from npm with their names with different sizes. In which scenarios we must downloads tanstack react query and for which react-query.
As far as I can tell the author chose to publish the new v4 version on @tanstack/react-query whilst keeping the v3 version on react-query.
So most likely, you want the latest version, which is @tanstack/react-query.
This is detailed here: https://tanstack.com/query/latest/docs/framework/react/guides/migrating-to-react-query-4#react-query-is-now-tanstackreact-query