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.
Also, please, can tell us what is inside the 3 combo boxes of the Project Properties => "C/C++ Build" => "Settings" => "Target" tab ?
You should have the STM32F1 then STM32F103VETHx and then your board name.
Is the board name empty ?