Does the Taiwanese law allow non native speakers with marriage ARC to teach English?

Although I am not from an English native speaking country, my command over the English language is pretty good. Also, as per my knowledge, with a marriage ARC, work permit is automatically granted. However, some employers tell me that they can only hire native speakers (to teach English) as per the law. So is having an open work permit limited to certain jobs and occupations?

It’s technically not an open work permit but a work permit exemption (unless you have an open work permit as a PR).

The short answer is that any job that’s available to a Taiwanese with the same qualifications should also be available to you (with some exceptions in politics etc.).