With .NET MAUI announced as the future of Xamarin.Forms, as expected .NET MAUI Essentials is the future of Xamarin.Essentials.
As of .NET 6 Preview 6 and .NET MAUI Preview 6, .NET MAUI Essentials is directly integrated. In fact, when you create a .NET MAUI app, it uses <UseMaui>true</UseMaui> in the .csproj and with this enabled and using Microsoft.Maui.Essentials added you get all of .NET MAUI Essentials into your project.
Additionally, if you are updating Xamarin.iOS or Xamarin.Android apps directly to .NET 6 without .NET MAUI, you can still use the APIs in Xamarin.Essentials simply by adding <UsingMauiEssentials>true</UsingMauiEssentials> into your .NET 6 iOS and Android apps.
As previously announced, this means that Xamarin.Essentials will be phased out. It will continue to be serviced through November 2022 with bug fixes. However new features and APIs will only be added to .NET MAUI Essentials