Remote Panel is blank when accessed from a subfolder in the URL

[Regnareb]

Describe the bug
I use reverse proxy to serve the remote panel to a subfolder and none of the .js file are recognized because a lot of links are absolute to the root of the web address.

For example with
https://domain.com/dashboard/
the file /_app/immutable/entry/start.bf487f06.js is looking at:
https://domain.com/_app/immutable/entry/start.bf487f06.js instead of
https://domain.com/dashboard/_app/immutable/entry/start.bf487f06.js

I tried fiddling in the 'resources/panel' files and fixed lots of path but to no avail, it stays blank. I think what is blocking me is mostly this part in index.html. I am not JS savvy and I don't know why it's not looking for the files in the right place when I modify it like the rest of HTML.

Promise.all([
    import("/_app/immutable/entry/start.bf487f06.js"),
    import("/_app/immutable/entry/app.3c109ba7.js")
]).then(([kit, app]) => {
    kit.start(app, element);
});

How to improve:
It would be great to have a web panel setting to be able to specify a subfolder/baseurl, or to use relative urls so it works in any configuration.

[Regnareb]

Also renaming index.html to dashboard.html doesn't work either.
And calling directly index.html in the URL does the same thing: https://domain.com/index.html

[Regnareb]

An issue in SvelteKit related to that: sveltejs/kit#9569