There is a serious inconsistency in how UTXO are referred.
On one hand, there is all the work of having a totally ordered consensus of transactions: the block chain. It would have been extremely simple to refer to a transaction output in a block chain: the block number, the transaction number in the block, and the output number in the transaction uniquely specify the UTXO. No need for a hash, no need for 256 bit !
Seriously you need to stop pretending you know anything about blockchain design.
This is beginners' egregious error.
Lol you just flunked the most fundamental issue of decentralized systems, which is there is no total order.