How to use a local start page

Hi there.

I have a start page. Currently it’s hosted on my website so I can use it with browsers.
I have used the external sites plug in coupled with the app order plug in to enable it to be the landing page for my self hosted nextcloud docker instance. It works well, except that nextcloud doesn’t seem to want to remember the (separate) log in details for the start page access, meaning I end up with two logins quite often.

I would like to ‘host’ the start page within nextcloud (or my dsm where this is all kept) so that the nextcloud instance can read it locally to avoid this problem. It doesn’t need external access or anything, I just want the html/js/css package to be able to be used without needing a www address.

Any ideas?