In time-based ordering, I don't understand how would users originally agree on the idea of FCFS, when the whole idea of arbitrage opportunities depends on increasing the fee to be placed earlier in the block (I mean this way you may place a regular TX, maybe an NFT minting or a good buying order before an arbitrageur TX? or it includes details for making separate blocks for such "arbitrage -wars" TXs as Dan Boneh said move your battle away from us inoconent people?) . -For the VDF solution, I guess this copes with POS Blockchains that use VDFs for choosing the block proposer (explained in Tim Roughgarden lecture series)