Transaction JSON objects from all eras now contains an extra field raw, which represents the raw serialized transaction (CBOR) as a base64-encoded text string. This is the case of the chain-sync protocol, but also for the tx-monitor protocol. The field is however absent in the ogmios.v1:compact mode. See https://github.com/CardanoSolutions/ogmios/issues/190.
That means we can now deserialize cborbase64 with CSL and implement getTxByHash without the need to decode Json.
From Ogmios changelog
That means we can now deserialize cborbase64 with CSL and implement getTxByHash without the need to decode Json.