Pre-Merge and Post-Merge transactions: Can a transaction be completed just before and just after?

1M Ago
For Ethereum users, will there need to be an update to hardware or software to interact with the new Beacon chain? Ex. User with Hardware Wallet + Metamask Pre-merge moment (POW): User uses a DEX to Swap 1 ETH for DAI. Post-merge moment (POS): User uses a DEX to Swap DAI for 1 ETH. Does something need an update or is the ledger and Metamask just suddenly going to route the transaction to the new chain? Does the DEX code just run on the new chain automatically?