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.
The selected value (0x20020000) is not the entry point, it is the initial stack pointer value, to modify it you can modify the _estack value in the linker file (.ld)