Since Taproot was activated, we no longer need separate OP_RETURN outputs to be pushed on-chain. If we want to attach any data to a transaction, we can create "OP_RETURN <anything>" as a branch in the TapScript. In this way, we can store that data off-chain and we can always prove that they are connected with some taproot address, that was pushed on-chain. Also, we can store more than 80 bytes for "free", because no such taproot branch will be ever pushed on-chain and used as an input. That means we can use "OP_RETURN <1.5 GB of data>", create some address having that taproot branch, and later prove to anyone that such "1.5 GB of data" is connected with our taproot address.
 
Currently in Bitcoin Core we have "data" field in "createrawtransaction". Should the implementation be changed to place that data in a TapScript instead of creating separate OP_RETURN output? What do you think?