PWA works on "/index.html" but not "/"

I created an Angular PWA and it works if you visit https://domain.tld/index.html. The index.html is also removed from the URL since "/" is equivalent to the index.

With that said if you refresh the page offline it no longer works as expected. The url changes to https://domain.tld/. If you are offline and visit https://domain.tld/index.html it works and it's served from the cache. So it only works if you access /index.html if you visit "/" it throws a 504.

I don't know how to solve this issue.

ngsw-config.json:

{
  "$schema": "./node_modules/@angular/service-worker/config/schema.json",
  "index": "/index.html",
  "assetGroups": [
    {
      "name": "app",
      "installMode": "prefetch",
      "resources": {
        "files": [
          "/favicon.ico",
          "/index.html",
          "/manifest.webmanifest",
          "/*.css",
          "/*.js"
        ]
      }
    },
    {
      "name": "assets",
      "installMode": "lazy",
      "updateMode": "prefetch",
      "resources": {
        "files": [
          "/assets/**",
          "/*.(svg|cur|jpg|jpeg|png|apng|webp|avif|gif|otf|ttf|woff|woff2)"
        ]
      }
    }
  ],
  "dataGroups": [
    {
      "name": "daily-api",
      "urls": ["https://api-link.net/daily.json"],
      "cacheConfig": {
        "strategy": "freshness",
        "maxSize": 10,
        "maxAge": "3d12h",
        "timeout": "3s"
      }
    }
  ]
}

I thought the issue might be the "index" property but I don't understand why "/" != "/index.html" for the offline PWA.

I'm using nginx to serve the content so maybe that is the issue?

....

index         index.html;

location / {
    try_files $uri $uri/ /index.html;
}

...

My angular routes consist of:

const routes: Routes = [
  {
    path: '',
    loadChildren: () => import('./rooms/rooms.module').then(m => m.RoomsPageModule)
  },
  {
    path: 'rooms',
    redirectTo: '',
    pathMatch: 'full'
  },
  {
    path: '**',
    redirectTo: '',
    pathMatch: 'full'
  }
];

I'm at a loss for trying to solve this. I can't seem to find any resources with why offline works on index.html but not on /.