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 now tried to reinstall openworkbench via an eclipse extension instead of the standalone installer and now it works again.
Somewhat strange but maybe this might help somebody out too.