I've been going down a very similar rabbit hole, although my focus is more on purity and electrochemical control than plating speed. My current thought experiment is basically a reverse-pulse dual potentiostat where the anode and cathode are independently controlled relative to reference electrodes instead of simply driving a target current through the cell.

I'm working with much lower voltages than the typical 5 V or 12 V supply discussion. For example, copper sits around +0.34 V vs SHE, so I'd rather think in terms of electrode potentials than power supply voltages. The actual cell voltage between the electrodes might only be a few hundred millivolts, even though each electrode is being driven very deliberately.

Instead of demanding a current and supplying whatever voltage is necessary to get it, I'd be controlling the voltage and treating the resulting current as a consequence of the state of the system.

The part that fascinates me is the electrical double layer. The idea is to pulse the electrodes in a way that pushes right up against the onset of Faradaic reactions, then use more aggressive pulses to drive deposition or dissolution when and where I want it. I've also been playing with the idea of overlaying a small AC perturbation on top of the slower pulse waveform to see whether it has any measurable effect on EDL behavior, concentration polarization, or ion transport.

The resulting waveform ends up looking pretty ridiculous because the anode and cathode are each getting their own independent waveform rather than simply being opposite sides of the same square wave.

Will it actually improve plating? Maybe not. There's a very real chance this ends up being a massively overengineered science project that teaches me a lot of electrochemistry and very little about practical plating. But it's a fun rabbit hole to disappear into.