Maybe try renaming the file to remove the ".x86" suffix and make sure that
directory is in the PATH?

e.g.:

    addToPath C:/full/path/to/dir/bin

I'm looking at the sample code you sent now.  It appears that the assembly
"GRPCRemoteClient" is not signed with a strong name.  This may have impact
on the type resolution.  The following appears to work:

    object create -verbose -alias "GRPCRemote.GRPCRemoteClient, GRPCRemoteClient, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" $host $port

This uses an assembly qualified name.

Using the above change and one additional change to the **assemblyResolve**
procedure, I am able to get the wrapped script working here locally.  Here
is the modified **assemblyResolve** procedure:

    proc assemblyResolve { sender e } {
      # NOTE: The next [if] was added.  If the assembly name being resolved
      #       should NOT be handled by us, return null.
      if {[$e Name] in [list UnityEngine Xamarin.iOS Mono.Android]} then {return null}

      global dll_dir

      regexp {^([^,]+),.+$} [$e Name] -> name
      log "name = $name"

      set fileName [file join $dll_dir $name.dll]
      log "fileName=$fileName"

      set type [load_type $fileName]
      log "type=$type"

      return $type
    }

If you like, I can send you the modified script via email; however, the above (two) changes
are apparently all that was required so far.