If not a coinbase transaction, you have to spend from an existing output. Thus the input must reference an existing transaction.
cannot retrieve the previous tx_hash
Maybe the library you are using is the following common semantic:
txid for the transaction id (hash without the witness data)
tx_hash for the transaction hash (hash with the witness data)
If there’s a case of a majority hashrate, human intervention of a single instance can not prevent something that continuous and ongoing. The amount of coordination required to keep the network in consensus would be impossible to obtain if this were a solution.
If Bitcoin fails, it’s time to move on rather than patching it up.