Wistia has a nice new uploader, but if you're trying to integrate it into a project using modules they don't support that.
The handle needs to be created once.
import wistiaPromise from 'wistia/external';
wistiaPromise().then(Wistia => {
const uploader = new Wistia.Uploader({
...
})
})
After its been created once, you can access the handle directly
import { Wistia } from 'wistia/external';
const uploader = new Wistia.Upliader({ ... });