If you use the full version of RT-Thread, the size compiled by GCC is generally large. It is recommended that you create a simplified version of RT-Thread nano type project, so that the size will be smaller. If you want to create a release build configuration, you need to create it based on the debug configuration. You need to know how to set the gcc compiler parameters to reduce the compiled size.
create a new build configuration by this menu
Ask RT-Thread Studio - release build