the 32bitpref corflag isn't part of a .net core target since those are always il, it is more properly a runtime concern as it should be
it's still the default in .net as of 4.8.1 (has been since it was introduced in 4.5 roughly coinciding w/java's pointer compression feature which is also still the default today)
The .NET Framework target might as well not exist :D
Many libraries are straight up dropping NS2.0 TFM and overall community tends to perceive the request to still target it very negatively. Sure, Visual Studio still runs some in-process features on top of it, and so do Office add-ins, but it's an active work-in-progress to get rid of any new code having to be written while still targeting it.
it's still the default in .net as of 4.8.1 (has been since it was introduced in 4.5 roughly coinciding w/java's pointer compression feature which is also still the default today)