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

OpenOCD "Dropped 'gdb' connection"


I think you put the “-f board/stm32h7x3i_eval.cfg” option on the wrong place because the error tells that the option was put for GDB command instead of OpenOCD command (Failed to execute MI command: -f board/stm32h7x3i_eval.cfg ) which make the debugger failing to start.
I don’t think using STLINK-V3E is the problem. Your console output says it is found and identified (Info : STLINK V3J3M2 (API v3) VID:PID 0483:374E )

This forum is dedicated to System Workbench for STM32, I don’t know much about how GNU MCU Eclipse works. You should try to contact them on their forum to find your answer.