I've noticed that
esri/geometry/webMercatorUtils is no longer available in 4.6. It was available in 3.23. How can
it be used in 4.6 or do I have to include 4.6 and 3.23?
Take a look at this functionality matrix: Functionality matrix | ArcGIS API for JavaScript 4.6
It states that the module has been moved to webMercatorUtils | API Reference | ArcGIS API for JavaScript 4.6