The GDPR is only unpredictable if your business model is at best in a grey area with regards to it. The spirit of the law is actually very clear, and should your business model be compatible with it, you will be fine.

It isn't Europe's fault that the tech industry's only business model for the past decade has been about misusing personal data in ways people didn't expect or consent to (otherwise GDPR would not be a problem again since people will willingly opt-in).