Yup - I worked on a data warehouse project that was subject to GDPR. The way we did it is we didn't do any synthetic data generation, we just blanked out any PII fields with "DELETED". Then it's still possible to action a delete request, because the PK's, emails are the same as they are in production.

It's definitely possible to practice this while adhering to GDPR, but you do need to plan carefully, and synthetic data should only be used for local dev/testing, not data warehousing.