You can directly transfer the native token into the pool.

Code example

import { ethers, utils } from 'ethers';

const tx = await window.ethProvider.getSigner().sendTransaction({
      to: poolAddress,
      value: utilEther.parseEtherToWei(that.depositEth.toString(10))
    })
    const res = await window.ethProvider.waitForTransaction(tx.hash, 1)