First and foremost: if I understand correctly, currently when sending transactions a Cardano Node just takes a spending password, and then creates a transaction, decrypts a private key with a spending password, signs a transaction and submits it to blockchain. All of that is done undercover and cannot be affected by an application developer in a current form of Cardano. Please correct me if I’m wrong, though API method: https://cardanodocs.com/technical/wallet/api/v1/?v=1.6.0#section/Getting-Started/Sending-ADA would suggest that I’m not.
In an app that I’m integrating Cardano with, it is crucial to modify a process of signing a transaction - so I would like to get my hands on an actual unsigned transaction object, sign it myself and then submit it to blockchain. Is it possible to do in current Cardano form? If not - what do I need to do to achieve that? Would I need to write a custom Cardano node or is there an easier way?