Right you are, STM32H743. And there’s another board (Xibeca) that uses STM32H750 and a different audio codecs that has 6 input and 8 output channels.
OWL3 ports for them are not ready yet. Work on Magus was started some time ago, but when I tried to build it and run on mine it produced no audio. I couldn’t find out any obvious misconfiguration from just looking at its project code, unfortunately.
Also, I’m not sure how easy it would be to find a used Magus these days. But I know that there have been some updates in its hardware since initial Kickstarted run, i.e. to reduce amount of noise which can be a problem there due to having LEDs and display. I wouldn’t be surprised if there would be yet another update to hardware along with proper OWL3 support when it happens.
I don’t think there was any effort towards porting Witch yet, which is surprising as that device was launched with polyphonic patches that would benefit greatly from a faster MCU. Turns out that Martin started work on this less than a month ago. I’ve also noticed that they have it on sale in Befaco shop, I was told earlier that they’ve stopped sales due to running out of OWL2 boards and no support for OWL3. So it seems like firmware port is either ready or will be finished soon. Unfortunately I don’t have a Witch to test current state of firmware.
There is a totally new module in the works specifically for OWL3, I can only say that it has lots of physical controls compared to previous hardware.