Struggling to use VERCEL_URL with `@t3-oss/env-nextjs`

 import { createEnv } from "@t3-oss/env-nextjs";
import { z } from "zod";

export const env = createEnv({
  server: {
    // .... server items
  },
  client: {
    NEXT_API_APP_TOKEN: z.string().min(1),
    NEXT_PUBLIC_APP_URL: z.string().url(),
  },
  runtimeEnv: {
    // App
    NEXT_PUBLIC_APP_URL: process.env.NEXT_PUBLIC_APP_URL,
    NEXT_API_APP_TOKEN: process.env.NEXT_API_APP_TOKEN,

    // ... set all server env's
  },
});

if (process.env.NODE_ENV === "development") {
  process.env.NEXT_PUBLIC_APP_URL = "http://localhost:3000";
}

if (process.env.VERCEL_URL && !process.env.NEXT_PUBLIC_APP_URL) {
  process.env.NEXT_PUBLIC_APP_URL = `https://${process.env.VERCEL_URL}`;
}