Calling a function from one javascript file from another

I have a webpage that calls a function from one javascript file on page load. This function then needs to call another function from a different javascript file.

Boiled down to its simplest form, it looks like this:

HTML File

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Website</title>
    <script type="module" src="testing2.js"></script>
    <script type="module" src="testing.js"></script>
</head>

<body onload="testFunc()">
    <div>
    </div>
</body>

JavaScript File 1

import { returnTrue } from './testing2.js';

export function testFunc(){
    console.log(returnTrue())
}

JavaScript File 2

export function returnTrue(){
return true;
}

Running this through a live server throws the following error though:

testing.html:12 Uncaught ReferenceError: testFunc is not defined
at onload (testing.html:12:27)

I know it has something to do with the fact that I’ve turned both the scripts into the type=”module in the HTML file, but I need to do that in order to import the one javascript file to the other.

Any help would be beyond appreciated. I know there’s a good chance that this has been answered already but I’ve run through dozens of different answers on the site and none of them resolve the problem 🙁