System.Runtime.InteropServices.COMException (0x800703FA): Retrieving the COM class factory for component with CLSID {82EAAE85-00A5-4FE1-8BA7-8DBBACCC6BEA} failed due to the following error: 800703fa Illegal operation attempted on a registry key that has been marked for deletion. (0x800703FA).
at System.RuntimeTypeHandle.AllocateComObject(Void* pClassFactory)
at System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean wrapExceptions)
at System.Activator.CreateInstance(Type type, Boolean nonPublic, Boolean wrapExceptions)
at System.Activator.CreateInstance(Type type)
at …

Solution

moved instance into ctor

public KeoObj()
{
  _proxiLab = (IProxiLAB)Activator.CreateInstance(Type.GetTypeFromProgID("KEOLABS.ProxiLAB"));
}

always a charm, clean code:

31 Best Clean Code C# Tips of 2023

possible relevance:

https://stackoverflow.com/questions/21941216/using-application-pool-identity-results-in-exceptions-and-event-logs

link base:

http://adopenstatic.com/cs/blogs/ken/archive/2008/01/29/15759.aspx