you want this to be applicable to UTXOs but you completely fail to show how UTXOs function like cash bills.
a 100k sat utxo with coinjoin history is NOT "considered entirely equivalent" to a 100k sat straight from a miner.
your peer might not care,
but he CAN *distinguish* between them.
unlike cash bills.
for a value transfer system to be fungible, units must be BOTH 1. equal and 2. indistinguishable.
therefore UTXOs are not fungible like cash bills.