Thank you so much for providing this information - these courses were flagged by other users as well, and I have reported them to the certification operations team (who will in turn report the infringements directly to Udemy).
I would definitely recommend leveraging the learning paths and content related to each certification at cloud.google.com/certification - most paths can be completed on Google Cloud Skills Boost, but we also have (official and approved) content available on Coursera and Pluralsight that is linked from that page.
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