I don't think what you are saying holds. For instance, 32k [0] is just where intersection of both .NET frameworkd (Win only) and .NET Core (cross plat). If you want to see in total, this is a rough estimation, 634k APIs [1]. I don't know how much of that is .NET core only.
[0] https://devblogs.microsoft.com/dotnet/announcing-net-standar...
[1] https://apisof.net/