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.
STutils, i don't know but "STlink Utility" for windows or "STM32 Cube Programmer" for all OSes, yes, the STLink fw upgrade is integrated and you can check the version.