Can an Attacker Use a 51% Attack to Steal Funds from a Smart Contract’s Locked Balance?

No, an attacker cannot directly steal funds locked in a smart contract merely by executing a 51% attack. The attack allows for transaction censorship and double-spending, but it does not grant the attacker the private keys or the ability to override the contract's code logic.

The attacker could, however, try to censor a transaction that would have prevented a malicious action they had previously initiated.