Firefox extension: Want to remove all cookies of activeTab if certain domain is loaded

Question

I am kinda struggling with porting a private chrome extension to firefox. My goal is the following: After a page is loaded, I want to delete all cookies from certain domains (which are stored in a list). I try to retrieve all cookies in my code, but I always get an array of length 0 as a return.. My manifest:

{
  "manifest_version": 3,
  "name": "My Addon",
  "version": "1.0",
  "description": "Description of my addon",
  "permissions": ["tabs", "cookies", "activeTab", "webNavigation",
  "webRequest"
  ],
  "host_permissions": ["<all_urls>"],
  "background": {
    "scripts": ["background.js"] 
    },
  "icons": {
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "action": {
    "default_icon": {
      "48": "icons/icon48.png",
      "128": "icons/icon96.png"
    }
  }
}

and my background.js:

browser.tabs.onUpdated.addListener(async (tabId, changeInfo, tab) => {
  if (changeInfo.status === "complete" && tab.url) {
    const domains = ["nzz.ch", "faz.net"]; // Hier kannst du weitere Domänen hinzufügen
    const cookies = await browser.cookies.getAll({});
    console.log("Alle Cookies:", cookies);
    for (const domain of domains) {
      if (tab.url.includes(domain)) {
        console.log(`${domain} loaded`);
        cookies.forEach(cookie => {
          if (cookie.domain.includes(domain)) {
            console.log("Deleting cookie:", cookie.name);
            browser.cookies.remove({
              url: `http${cookie.secure ? 's' : ''}://${cookie.domain}${cookie.path}`,
              name: cookie.name
            });
          }
        });
      }
    }
  }
});

As I am new to developing webextension, I would like to also understand what I am doing wrong, such that I can improve.

I expected an non-empty array of cookies.