How do I override DisplayFor boolean?

For true/false use DisplayTextFor by Justin Grant

For yup/nope based on Nuri YILMAZ, this is .NetCore 2.2, to downgrade replace HtmlString with MvcHtmlString:

1) C# write new extension DisplayForYZ

public namespace X.Views.Shared
{
    public static class DisplayExtensions
    {
        // If this was called DisplayFor not DisplayForYZ, we'd get recursion
        public static IHtmlContent DisplayForYZ<TModel, TValue>
          (this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression) 
        where TModel : Y
        {
            object o = expression.Compile().Invoke(html.ViewData.Model);
            // For any bool on TModel, return in this custom way:
            if (o.GetType() == typeof(bool))
            {
                return (bool)o ? new HtmlString("Yup") : new HtmlString("Nope");
            }
            // Otherwise use default behaviour 
            return html.DisplayFor(expression);
        }
    }
}

2) cshtml: Import the DisplayExtensions namespace and use new extension.

@model X.ViewModels.Y
@using X.Views.Shared;

@Html.DisplayForYZ(modelItem => modelItem.Z)   @*//Yup/Nope*@
@Html.DisplayForYZ(modelItem => modelItem.A)   @*//default non bool behavior*@

@Html.DisplayFor(modelItem => modelItem.Z)     @*//check box*@
@Html.DisplayTextFor(modelItem => modelItem.Z) @*//true/false*@

X = {my company} Y = {object for customised display} Z= {bool property} A= {non-bool property}