> Domestically these countries have entities collecting personal data in the same evil way as US entities
Can you provide sources for this allegation?
I don't know where you are getting your information from but that's not true.
> careful when buying stuff online
I know what I'm doing online. You sound like communication from most of retail banks.
If you are so certain that you are right and that you 'know what you are doing online,' have you reported this incident to law enforcement? It would benefit everybody. Could you also specify which healthcare service providers you believe sold your data? This information could help others avoid using them.
1. provide details about how the data was collected according to GDPR's Article 14 paragraph 1, I also request the information they should provide as delineated by paragraph 2.
2. send you all the data related to your person according to GDPR's Article 15.
3. complete erasure of all personal data they have collected in accordance with GDPR's Article 17.
So far I have not had to contact the Swedish DPA since the few times it happened the companies actually followed my GDPR request.
Edit: and even if you have given consent through some GDPR form you can withdraw it at any time, contacting the company with a GDPR request and explicitly stating you withdraw all consent to their processing of personal data should be enough.