Is it possible to render an external URL via a control add-in?

I am working on a punchout application for Business Central and I would like to redirect a user to external URL via a control add in. Right now I have a startup script

Microsoft.Dynamics.NAV.InvokeExtensibilityMethod('ControlReady', []);
console.log("Add-in initialized");

an "openUrl" script

(function () {
    console.log("Add-in started");
    window.PunchoutCatalogAddIn = {
        OpenUrl: function (url) {
            window.open(url, '_blank');
        }
    };
})();

the control add in object

controladdin PunchoutCatalogAddIn
{
    StartupScript = './scripts/startup.js';
    Scripts = './scripts/openurl.js';

    RequestedHeight = 700;
    MinimumHeight = 700;
    MaximumHeight = 700;

    RequestedWidth = 700;
    MinimumWidth = 700;
    MaximumWidth = 700;

    VerticalShrink = true;
    HorizontalShrink = true;
    VerticalStretch = true;
    HorizontalStretch = true;
    event ControlReady();
    procedure OpenUrl(url: Text);
}

and the page the user interacts with

page 50114 PunchoutCatalog
{
    PageType = Card;
    ApplicationArea = All;
    Caption = 'Open External URL';

    layout
    {
        area(content)
        {
            usercontrol(PunchoutCatalogAddIn; PunchoutCatalogAddIn)
            {
                trigger ControlReady()
                begin
                    Message('PunchoutCatalogAddIn control is ready.');
                end;
            }
        }
    }

    actions
    {
        area(processing)
        {
            action(OpenCatalog)
            {
                Caption = 'Open Catalog';
                trigger OnAction()
                begin
                    Message('Attempting to open URL: %1', ResponseUrl);
                    if ResponseUrl = '' then
                        Error('Response URL is empty.');

                    CurrPage.PunchoutCatalogAddIn.OpenUrl(ResponseUrl);
                end;
            }
        }
    }

    var
        ResponseUrl: Text;

    procedure SetResponseUrl(Url: Text)
    begin
        ResponseUrl := Url;
        Message('Response URL set to: %1', Url);
    end;
}

The strange thing is that, although the openUrl script is run (it console logs "add-in started"), it does not appear in the DOM when I go to inspect the browser, and nothing renders in the iframe. Could someone point me in the right direction? Thank you in advance!

If all you want to achieve with the Control Add-in is to open an external URL, you should use the built-in WebPageViewer.

You just add it to the page as a usercontrol:

usercontrol(PunchoutCatalog; WebPageViewer)
{
    ApplicationArea = All;

    trigger ControlAddInReady(CallbackUrl: Text)
    begin
        CurrPage.PunchoutCatalog.Navigate(ResponseUrl);
    end;
}

You don't have to call CurrPage.PunchoutCatalog.Navigate() from the ControlAddInReady trigger.
It is available from anywhere on the page you added the usercontrol to.