SW4STM32 and SW4Linux fully supports the STM32MP1 asymmetric multicore Cortex/A7+M4 MPUs

   With System Workbench for Linux, Embedded Linux on the STM32MP1 family of MPUs from ST was never as simple to build and maintain, even for newcomers in the Linux world.
And, if you install System Workbench for Linux in System Workbench for STM32 you can seamlessly develop and debug asymmetric applications running partly on Linux, partly on the Cortex-M4.
You can get more information from the ac6-tools website and download two short videos (registration required) highlighting:

System Workbench for STM32

No longer able to program my NUCLEO-H743ZI

Well, it’s good to get the obvious stuff out of the way first.
Yes, a reboot would solve the zombie process thing.

I take it you have checked the device is actually available on USB? On Linux I would use the ‘lsusb’ command, I think on MacOS you’d have to use the System Profiler tool.
If you can’t see it you are back to cables and connectors (or a dead ST-Link)

If that works, next step is try a tool that doesn’t use OpenOCD - eg: the STMCubeProgrammer tool which will try and discover the device and, very usefully, upgrade the software in the ST-Link interface itself (there’s a little STM32 that does the USB to ST-Link task separate to the STM32H743ZI on your Nucleo board.