You can top up your Argent X wallet using Layerswap from your Ethereum mainnet addresses in Coinbase, Binance, Kraken wallet and many more exchanges to choose from.
For this navigate to https://www.layerswap.io/?destNetwork=starknet_mainnet and proceed with the on-screen instructions. You can also access Layerswap using Add funds menu in your Argent X wallet.
Please do not change the destination network (To field should remain StarkNet)
Here you can find individual guides on using Layerswap based on your wallet/exchange: