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.
One of the first lines in main.c is defined( USE_BAND_915 ) so just put the setting in the preprocessor defined settings in the properties of the project.