public class MyViewLocationExpander : IViewLocationExpander
  {
    public IEnumerable<string> ExpandViewLocations(ViewLocationExpanderContext context, IEnumerable<string> viewLocations)
    {
      if (context.ControllerName != null && context.ControllerName.StartsWith("App"))
      {
        viewLocations = viewLocations.Concat(
          new[] { $"/Areas/sysManage/Views/App/{context.ControllerName}/{context.ViewName}{RazorViewEngine.ViewExtension}"
              });
        return viewLocations;
      }

      if (context.AreaName != "sysManage") return viewLocations;
      viewLocations = viewLocations.Concat(
        new[] { $"/Areas/sysManage/Views/System/{context.ControllerName}/{context.ViewName}{RazorViewEngine.ViewExtension}"
        });
      return viewLocations;
    }

    public void PopulateValues(ViewLocationExpanderContext context)
    {
    }
  }

 public void ConfigureServices(IServiceCollection services) 
    { 
      services.Configure<RazorViewEngineOptions>(o => { 
        o.ViewLocationExpanders.Add(new MyViewLocationExpander()); 
      }); 
      services.AddMvc(); 
    } 

 app.UseEndpoints(endpoints =>
      {
        endpoints.MapRazorPages();
        endpoints.MapAreaControllerRoute(
          name: "sysManage", "sysManage",
          pattern: "{area:exists}/{controller=Home}/{action=Index}/{id");
      });

/SysManage/Controller/Action