Have you tried reaching out to Dell on the chat? We buy the Precision laptops in Switzerland, and there's a number of keyboard options (including US)[0]. I checked Dell UK for a similar device [1] but they only have German, UK or French listed.

[0] - https://www.dell.com/de-ch/work/shop/notebooks/neu-xps-15/sp...

[1] - https://www.dell.com/en-uk/work/shop/laptop-computers-for-bu...

(edited for formatting of references)