NativeScript Core already contains a polyfill for XMLHttpRequest here:
https://github.com/NativeScript/NativeScript/blob/main/packages/core/xhr/index.ts

Canvas-polyfill uses its own polyfill: https://github.com/NativeScript/canvas/blob/master/packages/canvas-polyfill/async/xhr/TNSXMLHttpRequest.ts

This breaks functionality for libraries that use default NS polyfill (e.g. axios).