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.
attached the bad .cproject file, maybe it helps. I have added some folders to my project with source and header files to Paths and symbols. Is it possible that is causing the problem?