Hi. I will answer your question here, but there is a forum for Adobe Stock that would be a better place for this question:
https://community.adobe.com/t5/stock/ct-p/ct-stock?page=1&sort=latest_replies&filter=all&lang=all&ta...
If I call this same url and I subscribe an Enterprise plan the image will be full sized and without watermark?
No, not necessarily. Having an Enterprise plan does not provide access to unwatermarked previews automatically; however, it is an option. Note that you cannot sign up for enterprise online and use a credit card. You must meet with a sales team and go through a formal contract process. During that time, you can request any features you need, and they will be priced according to your usage. For more info on this program, see: https://www.adobe.com/creativecloud/business/cce-4.html
Furthermore, URLs to unwatermarked previews will not come from a CDN endpoint such as Files or Search. There are private APIs for this use that require authentication.
I hope this answers your question.
Thanks,
Christopher