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.
I'm using one of these cheap ST-Link V2 adapters from Ebay.
It is connected only with SWCLK, SWDIO and GND to a "bluepill" (Maple Mini clone) PCB. for programming and debugging.
Thanks for the hints.