GDPR has only been around for a few years, but other data protection legislation in various countries has been around since the late 1990s, for example, here in the UK we had the Data Protection Act 1998.
Apparently, Finland had the Personal Data Act since 1999 (prior to GDPR), and presumably it was under this that their Data Protection Ombudsman first ruled the JWs should not be collecting door-to-door info without the knowledge and consent of the householder.
Point 5 of The Facts section in the latest ruling says: "In October 2000 the Data Protection Ombudsman (tietosuojavaltuutettu, dataombudsmannen – “the Ombudsman”) issued an opinion (89Û/45/97) about the applicant community’s data collection practices indicating, inter alia, that personal data could be collected in the course of door-to-door preaching by individual Jehovah’s Witnesses only with the consent of data subjects."
So yes, it seems the org's lawyers have dragged this on for 23 years!
In Europe at least, those S8 house-to-house records are well and truly dead. If there are any EU countries where branches have not yet withdrawn them and stopped the congregations taking their own records, they will presumably have to do that now.