Custom endpoint that returns an xml

I need to create an endpoint that when called returns an XML with the products of the store. I have the XML generated, but I don’t know how to make the endpoint return it in XML format, because now it returns it in JSON format, and being an XML, it does not return it well.

Dynamic Endpoints

I have a database table outside WordPress that I need to make endpoints for. I’ve created a page /cars/ where I plan on using a page template to generate links. I would like for the url to look like /cars/camaro/ ( /cars/%model%/ ). Originally I thought I could do it with endpoints but wasn’t sure how to make them dynamic based off of the slug pulled from the Model Table. I also wasn’t sure if it would be easier using Permalink Structure tags or which was better.