This particular delay in completing withdrawals was caused by congestion on the L1 side. The Optimism network uses a failover window that can extend up to seven days on the canonical path, which catches many by surprise. A faster solution exists through third-party liquidity providers, which bypass this window entirely by using a bridge. One such option is listed here
https://defiway.com/bridges/bridge-eth-optimism-ethereum They process ETH transfers between the two chains. Checking the transaction hash in an L1 explorer will at least confirm whether the relay message was received.