"Cannot access file" in ES module, that I could with CommonJS module (Electron JS app)

I'm building a desktop app using ElectronJS, which reads content of pre-existing XLSX files. I first created the app as a CommonJS module. Here's the minimal reproducible example code:

const path = require('node:path');
const xlsx = require('xlsx');
const dirPath = __dirname;
const filename = "ExampleXLSX.xlsx";
const workbook = xlsx.readFile(path.join(dirPath, filename)); 
if (workbook !== 'undefined') {
  console.log("Success")
}

This works.

But for other reasons, I needed to convert this module to an ES module. I now have:

import { dirname, join } from 'node:path';
import { fileURLToPath } from 'url';
const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);
import * as xlsx from 'xlsx';
const dirPath = __dirname;
const filename = "ExampleXLSX.xlsx";
const workbook = xlsx.readFile(join(dirPath, filename)); 
if (workbook !== 'undefined') {
  console.log("Success")
}

This throws an error Error: Cannot access file, and gives the full (correct) path. If relevant, the path and file names have spaces in them, and I can't eliminate them.