My attempt at a GDPR-Compliant Privacy Policy:

Information I Collect

To fulfil your order, you must provide me with certain information (which you authorized Etsy to provide to me), such as your name, email address, postal address, payment information, and the details of the product that you’re ordering. You may also choose to provide me with additional personal information (for a custom order of jewelry, for example), if you contact me directly.

Why I Need Your Information and How I Use It

I rely on a number of legal bases to collect, use, and share your information, including:

as needed to provide my services, such as when I use your information to fulfil your order, to settle disputes, or to provide customer support;
when you have provided your affirmative consent, which you may revoke at any time, such as by signing up for my mailing list;
if necessary to comply with a legal obligation or court order or in connection with a legal claim, such as retaining information about your purchases if required by tax law; and
as necessary for the purpose of my legitimate interests, if those legitimate interests are not overridden by your rights or interests, such as 1) providing and improving my services. I use your information to provide the services you requested and in my legitimate interest to improve my services; and 2) Compliance with the Etsy Seller Policy and Terms of Use. I use your information as necessary to comply with my obligations under the Etsy Seller Policy and Terms of Use.

Etsy. I share information with Etsy as necessary to provide you my services and comply with my obligations under both the Etsy Seller Policy and Etsy Terms of Use.
Service providers. I engage certain trusted third parties to perform functions and provide services to my shop, such as delivery companies. I will share your personal information with these third parties, but only to the extent necessary to perform these services.
Business transfers. If I sell or merge my business, I may disclose your information as part of that transaction, only to the extent permitted by law.
Compliance with laws. I may collect, use, retain, and share your information if I have a good faith belief that it is reasonably necessary to: (a) respond to legal process or to government requests; (b) enforce my agreements, terms and policies; (c) prevent, investigate, and address fraud and other illegal activity, security, or technical issues; or (d) protect the rights, property, and safety of my customers, or others.

Data Retention

I retain your personal information only for as long as necessary to provide you with my services and as described in my Privacy Policy. However, I may also be required to retain this information to comply with my legal and regulatory obligations, to resolve disputes, and to enforce my agreements. I generally keep your data for the following time period: 4 years.

Transfers of Personal Information Outside the EU

I may store and process your information through third-party hosting services in the US and other jurisdictions. As a result, I may transfer your personal information to a jurisdiction with different data protection and government surveillance laws than your jurisdiction. If I am deemed to transfer information about you outside of the EU, I rely on Privacy Shield as the legal basis for the transfer, as Google Cloud is Privacy Shield certified.