npm import : class is not found but it is well declared in node_module

import { Ethereum, Network, TatumSDK } from "npm:@tatumio/tatum";

const tatum = await TatumSDK.init<Ethereum>({ network: Network.ETHEREUM });
const latestBlock = await tatum.rpc.blockNumber();
console.log(`Latest block is ${latestBlock.result}`);
tatum.destroy();

// BigNumber.js has a version for deno !
// error: Uncaught (in promise) TypeError: R.BigNumber is not a constructor
import { Ethereum, Network, TatumSDK } from "https://esm.sh/@tatumio/tatum";

// fake call to prevent error
window.location = { hostname: "fake" };

const tatum = await TatumSDK.init<Ethereum>({ network: Network.ETHEREUM });
const latestBlock = await tatum.rpc.blockNumber();
console.log(`Latest block is ${latestBlock.result}`);
tatum.destroy();