Calling a SOAP web service from Javascript

I have a SOAP API that I am trying to call from a vanilla javascript website. However, I keep running into a CORS policy issue. I have used a proxy to get around it, but this I am calling this API from multiple different domains and the proxy seems to be very inconsistent.

I don't have access to the API coding or anything. The API that I am accessing is: https://developers.dealerbase.co.nz/

I don't want to use a proxy. But if someone could suggest a way on how to do this. For example: if the best way would be to say make a .net core website that calls the API and then that can be called by the vanilla website. I will do that.

I want to know what your thoughts are.

If you need anymore information please let me know.