The AEPD found breaches of the GDPR. Its view of the provider’s role rested on the facts of that service: its purposes, its influence on the processing and how recipients were informed. The case does not show that every paid provider is a controller, nor what happened in any later court review.
A contract does not move liability towards the authority: the AEPD’s guide on cookies says that splitting tasks between companies by contract does not transfer each party’s administrative responsibility.
This answer covers the Spanish decisions described in HawkOpen’s legal documents. It does not assess German warning letters (Abmahnungen) or sanctions in other countries.