How can I get the url pathname on a server component next js 13

Take a look at https://github.com/vercel/next.js/issues/43704 , pauliusuza solved this issue

You can do a workaround using a middleware

import { NextResponse } from 'next/server';

export function middleware(request: Request) {

  // Store current request url in a custom header, which you can read later
  const requestHeaders = new Headers(request.headers);
  requestHeaders.set('x-url', request.url);

  return NextResponse.next({
    request: {
      // Apply new request headers
      headers: requestHeaders,
    }
  });
}

Then use it from inside of a root layout:

import { headers } from 'next/headers';

export default function RootLayout() {
  const headersList = headers();
  // read the custom x-url header
  const header_url = headersList.get('x-url') || "";
}

Hope that helps