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.
OK, so I've just tried downloading the CubeHAL instead of StdPeriph, and it seems to be downloading... Looks like this is the newest thing anyway, so I'll probably persist with using the CubeHAL rather than StdPeriph!