Moralis crypto login

Is Moralis.Web3.authenticate() supposed to be used in the frontend or in cloud functions? It returns some sensitive data from the backend if I interpret the documentation correctly

It’s used in the frontend to login users

noted, so each chain will need a smart contract. I have done eth mainnet before, so I can use remix to deploy for polygon also ?

You can use Remix to deploy on a different chain, you will have to select the chain in metamask.