Is this from Spain?
It sounds like what they are doing is clearly illegal and you probably could do a lot of people a favor by complaining to the authorities.
Generally for the eu: https://www.europarl.europa.eu/doceo/document/E-8-2017-003934-ASW_EN.html “If users receive unsolicited communications after having withdrawn consent, they can file a complaint with the national regulatory authority. In addition, they have the right to a judicial remedy before national courts.”
The responsible agency for Spain: https://www.aepd.es/
It’s been a while since I used chrome, but I used to use incognito to avoid that from happening. You can log into your services in the incognito session and when you’re done and close the incognito session, the temporary folder with your session stuff will get deleted, leaving the normal chrome browser unaffected.