A transfer between different chains isn't the same as a regular one, and a lot of people get stuck right at that step without realizing why it's not working. You need a bridge for that, something that actually moves your ETH from Optimism over to Ethereum mainnet properly. You can bridge your Optimism ETH to Ethereum here: https://defiway.com/bridges/bridge-eth-optimism-ethereum . Just connect your wallet, pick the amount, and confirm the swap, it usually takes a few minutes depending on network congestion. Double check the amount before confirming since bridge transactions can't really be undone once they're sent.