Issues with Fragment deprecation

[LaurenNicoleSmith]

I'm trying to build this in Azure DevOps for a project, and since Fragment is a deprecated class, I've been trying to use the Support version, particularly in PageExtensions.cs. However, it keeps saying that the type or namespace could not be found in the global namespace and asking if I'm missing an assembly reference. From what I've found, it looks like there is the correct assembly reference in Xamarin.Forms.Platform.Android.csproj.
Any advice/thoughts would be much appreciated. Thanks in advance