Development tools for Zephyr on STM32Workbench for Zephyr: VS Code extension to set up, build, flash and debug Zephyr applications on STM32.Devicetree manager: browse, edit and visualize Zephyr devicetree, STM32CubeMX-like for Zephyr.
In your "Ac6 STM32 Debugging" profile, go to the "Debugger" tab, then in the OpenOCD setup, try to select "Manual Spec" and choose the ST-Link/V2 as device and the SWD as interface.