If it is a US company that does business in Europe, but is not established in the Union, you are correct.
If the company is established in the Union, then GDPR applies to all personal data processing it does. See Article 3(1): "This Regulation applies to the processing of personal data in the context of the activities of an establishment of a controller or a processor in the Union, regardless of whether the processing takes place in the Union or not."
The question, then, is Tesla merely a company that is offering goods and services to people in the Union, but not itself established in the Union, or is Tesla established in the Union?
If the company is established in the Union, then GDPR applies to all personal data processing it does. See Article 3(1): "This Regulation applies to the processing of personal data in the context of the activities of an establishment of a controller or a processor in the Union, regardless of whether the processing takes place in the Union or not."
The question, then, is Tesla merely a company that is offering goods and services to people in the Union, but not itself established in the Union, or is Tesla established in the Union?