.NET Framework 4.6.2+ (x86, x64, AnyCPU) no longer supported?

[negusm]

Looking at the list of supported frameworks it looks like 4.6.2+ is supported.

But the nuget package only loads for .Net 5.0 or higher.

If I take the DLL and reference it directly from a 4.7 (or 4.6.2) project, it builds but I get this error:
'Could not load file or assembly 'netstandard, Version=2.1.0.0'

Is there any prior versions that can be used?

I am looking to work with 4.7 since that is what Mono says it supports. So in short, this current version won't support mono either?