We have the Cervinodata API in beta available and got it to work with KNIME quite nicely. But we are looking for volunteers to test the Cervinodata API and create some open source use cases.
Based on that we can make specific adjustments to the Cervinodata API to make it easier for KNIME users to get the key metrics from multiple ad accounts and platforms together in one database. if you are interested, let me know.
Check out the documentation here: https://app.cervinodata.com/api/documentation