node-fetch-cookies is based on the v2.x releases of node-fetch, and the native FormData() is only supported by the v3.x releases, as it is only supported by Node.js since version 18.
If you want to send forms, there are two possibilities I'm aware of:

1. application/x-www-form-urlencoded: This is supported by node-fetch v2 using a native Node.js class:

   import fetch from "node-fetch";
   
   const postData = {
       wpUnicodeCheck: "ℳ𝒲♥𝓊𝓃𝒾𝒸ℴ𝒹ℯ",
       wpAntispam: null,
       wikieditorUsed: "yes"
   };
   var formData = new URLSearchParams(postData);
   console.log(formData);
   let response = await fetch('https://enahwvayvwxi.x.pipedream.net/', {
       method: "POST",
       body: formData
   });

2. multipart/form-data: This is also supported by node-fetch v2, but requires a third-party package:

   import fetch from "node-fetch";
   import FormData from "form-data";
   
   const postData = {
       wpUnicodeCheck: "ℳ𝒲♥𝓊𝓃𝒾𝒸ℴ𝒹ℯ",
       wpAntispam: null,
       wikieditorUsed: "yes"
   };
   var formData = new FormData(postData);
   for ( var key in postData ) {
       formData.append(key, String(postData[key]));
   }
   console.log(formData);
   let response = await fetch('https://enahwvayvwxi.x.pipedream.net/', {
       method: "POST",
       body: formData
   });

   Note that the form-data package doesn't automatically convert null, undefined and boolean values to strings, like the native FormData() does (Error when trying to write boolean type form-data/form-data#137). Thus, I've wrapped postData[key] in String().

Furthermore, you may want to have a look at this stackoverflow question, which provides answers on when to use which of the form data types.