Vendors do exist but they are not required to do so. My last job was at a software vendor, GDPR compliant, ISO & SOC 2 certified, controlling personal data (including salary information) of EU citizens who were not opted in (their employer is the one on the contract). Not healthcare levels of sensitive but still pretty icky in terms of EU law and we had tons of German friends who are real sticklers for the rules. We stored everything on AWS infrastructure and it has never caused any issue during certification or security assessment by clients.