A family of Microsoft suites of integrated development tools for building applications for Windows, the web, mobile devices and many other platforms. Miscellaneous topics that do not fit into specific categories.
The workaround is based on THOMAS LEVESQUE's .NET Framework approach (https://thomaslevesque.com/2021/11/12/building-a-project-that-target-net-45-in-visual-studio-2022/).
As older .NET Frameworks SDKs are missing from C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework, the same occurs with older .NET Core Templates.
First I must explain the differences between the two approaches. For the .NET Framework it becomes very difficult to obtain the SDKs for each version below 4.5.1, so it is almost mandatory to extract the libraries from the nuget packages of the series: Microsoft.NETFramework.ReferenceAssemblies.net(ver), to then extract (as compressed files) the contents of build.NETFramework\v(ver)\ to the local system folder.
But with .NET Core the scenario is somewhat simpler: It's easy to get the SDKs for .NET Core from https://github.com/dotnet/core/tree/main/release-notes/download-archives and install them on our OS without problems. And here comes the problem: Visual Studio 17 looks for the templates for project platform initialization in a folder (C:\Program Files (platform)\dotnet\templates) that does not contain templates from versions prior to .NET Core 3.0. However, these older versions have their own templates inside their respective folders: C:\Program Files (platform)\dotnet\sdk(ver)\Templates.
So, we just have to copy the content of the templates folder (C:\Program Files (platform)\dotnet\sdk(ver)\Templates), to a subdirectory named with the name of the .NET Core version in the global templates folder (C:\Program Files (platform)\dotnet\templates(ver)).
And that's how we're able to build software for .NET Framework versions from 2.0 to 4.8.x (I haven't found a compatible SDK for 1.0) and .NET Core + .NET from 1.0 to 7.x, keeping customers comfortable in their environments, and us as developers with a single version of Visual Studio.