On Ethereum, where block times are around 12 seconds, all stakeholders have the time to access all transactions and simulate all of them in order to maximize their profits. With this in mind, the current gold standard approach on Ethereum is Proposer-Builder Separation (PBS). This setup separates the process into 5 stakeholders: users, block producers, relays, block proposers, and searchers. By separating the block welfare value with multiple stakeholders, they are all incentivized to share information with each other, which allows for competitive block building, while ensuring blocks stay profitable (which minimizes failed transactions). This has its own issues though block producers have become centralized with the top two builders capturing more than half of the value from block building. Apps have also realized that they can capture their own MEV through mechanisms like MEV taxes, allowing them to participate in the transaction ordering process and reclaim value that would otherwise go to block proposers.