UXP plugin Upload active document using xhr to presigned URL

Photoshop UXP Plugin API
5

I’ve tried using let fileEntry = require(‘uxp’).storage.localFileSystem.getFileForOpening(), but get the Error: Plugin is not permitted to access the file picker.

I also tried using the method you suggested from this post Saving a JPG to a selected folder - #3 by 4t0m1c
I found I had to use executeAsModal but still can’t get it to save to a temporary folder.

const lfs = uxp.storage.localFileSystem;
const tempFolder = await lfs.getTemporaryFolder();
const saveFileToFolder = async (tempFolder, fileName="temp")  => {
          const file = await tempFolder.createFile(`${fileName}.jpg`);
          const activeDocument = require("photoshop").app.activeDocument;
          return activeDocument.save(file);
      }
        
        await require('photoshop').core.executeAsModal(saveFileToFolder);

It errors saying the createFile is not a function.

I just need a way to attach the active document’s file object to the fetch or xhr upload.