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.
Sorry for the long reply, I've been abroad the last two weeks. I've just tried the updated method to importing an mbed program and it built without any errors.