The current information available indicates that the RV1106 MCU is used for boot management, but Rockchip does not plan to release documentation on this part, so it cannot be determined whether using the MCU can reduce standby power consumption close to zero.
In the <Luckfox-pico SDK>/sysdrv/source/uboot/u-boot/arch/arm/mach-rockchip/rv1106/rv1106.c file, there are references to the startup and reboot processes involving the MCU. However, there are still significant obstacles to utilizing it effectively. At present, the most reliable approach appears to be utilizing an external MCU, despite the associated cost increase, as it would significantly reduce the complexity involved.