Removed Framework wise NuGet package for Syncfusion ASP.NET CORE (Essential JS 1) platform – v16.1600.0.xx
Starting from version 16.1.0.24, Syncfusion® updated the structure of its ASP.NET Core (Essential JS 1) NuGet packages. This update changed how frameworks are grouped and how package versions are displayed and managed.
As a result of this restructuring, when installing or updating the Syncfusion® ASP.NET Core package using the Syncfusion® private NuGet server feed
(https://nuget.syncfusion.com/nuget_aspnetcore/nuget/getsyncfusionpackages/aspnetcore), the latest stable version is always displayed as 16.1600.*.* in the Visual Studio NuGet Package Manager.
Please refer to the screenshot below for a visual reference:

The latest stable version is displayed incorrectly due to the numeric ordering of Syncfusion® ASP.NET Core package versions (1600 > 2), which is the default behavior of NuGet.
As part of the updated package structure, the framework-based
NuGet packages for Syncfusion® ASP.NET Core v16.1.0.xx (specifically
versions 16.1600.0.24, 16.1600.0.26, and 16.1600.0.32) have been removed
from the Syncfusion® private NuGet server. Instead, framework-grouped
packages are provided for these versions, offering a more streamlined and
consistent experience. You can find detailed information about the
framework-grouped Syncfusion.AspNet.Core packages here.
You will face the unable to find package issue when restoring the solution or project if still using the NuGet package version with Framework (eg., 16.1600.0.xx).

If you install the 16.1600.0.xx release version of Syncfusion® ASP.NET Core NuGet packages in your application and want to update your Syncfusion® ASP.NET Core (Essential JS 1) packages, and then update the required Syncfusion® ASP.NET Core (Essential JS 1) packages in one of the following ways:
Package Manager:
Update the Syncfusion® ASP.NET Core (Essential JS 1) packages by manually selecting the required version from the NuGet Package Manager drop-down.
Package Manager Console:
You can update the Syncfusion® ASP.NET Core packages using the Package Manager Console by specifying the required version:
> Update-Package <package id> -Version <version>