I used the settings below in the .overlay file to achieve the same thing.
This is why the board files on the zephyr branch that we discussed on the getting started comment section worked correctly for the zephyr_lowpower example. Those values are not set there, so the regulators are not on at startup. I think this is working because I see the expected low current usage when supplying voltage on the 5V pin. Without those settings, the current usage is high.
&pdm_imu_pwr{
/delete-property/ regulator-boot-on;
};
&vbat_pwr{
/delete-property/ regulator-boot-on;
};
&rfsw_pwr{
/delete-property/ regulator-boot-on;
};