1.Lynex is a dex built on Linea Layer2, this is its contract site:
https://lineascan.build/address/0x610D2f07b7EdC67565160F587F37636194C34E74#readContract

2.Lynex official site, and related contract address is here:
https://lynex.gitbook.io/lynex-docs/security/contracts

My full code is here:

const ethers = require('ethers');

const Constants = {
  WETH: ethers.utils.getAddress("0xe5D7C2a44FfDDf6b295A15c148167daaAf5Cf34f"),
  ezEth: ethers.utils.getAddress("0x2416092f143378750bb29b79ed961ab195cceea5"),
  router: "0x610D2f07b7EdC67565160F587F37636194C34E74",
  myWallet: "0x7C09b8fE224591E797c533Bb74f0eF79077c3f9C", // Change this to your address
}

const EthAmount = ethers.utils.parseEther('0.0003'); //.toHexString();
//const gasPrice = ethers.utils.parseUnits('10', 'gwei');

const privateKey = "my_private_key"; // process.env.PRIVATE_KEY;
const provider = new ethers.providers.JsonRpcProvider('https://rpc.linea.build');
const account = new ethers.Wallet(privateKey,provider);

const lynexRouterAbi = require('../abi/lynexRouter.json');
const router = new ethers.Contract(Constants.router, lynexRouterAbi, account);

const snipe = async (token) => {
  tokenA = Constants.WETH;
  tokenB = Constants.ezEth;

  // get wETH ca
  var weth_ca = await router.wETH();
  console.log("weth: ", weth_ca);

  // get factory ca
  var factory_ca = await router.factory();
  console.log("factory_ca: ", factory_ca);

  const tx = await router.swapExactETHForTokens(
    0, // Degen ape don't give a fuxk about slippage
    [tokenA, tokenB],
    Constants.myWallet,
    Math.floor(Date.now() / 1000) + 60 * 10, // 10 minutes from now
    {from : account.address , value: EthAmount , gasLimit: 251234}
  );
  console.log(`Swapping wETH for tokens...`);
  const receipt = await tx.wait();
  console.log(`Transaction hash: ${receipt.transactionHash}`);
  console.log("snipe done!");
}

(async () => {
  await snipe();
})();

I just use node script.js, but got this error:
enter image description here