Is power control to Pi or to PiJuice (battery)? Can I switch off USB power to Pi?

[kurijn]

Hello
Rather new to the Pi and PiJuice I'm setting up a system with a solar panel and (including extra battery) which delivers its power over USB. There is also an emergency USB-adapter which I only want to rely on when all battery power is getting to the low treshold.
I have a Pi4 with USB-C (now connected to the adapter) and the PiJuice HAT, whose micro-USB is used for the solar power input.
I wondered in the first place if at all the power of the adaptor can be shut off with the PiJuice (or other) API while the Pi is still running using power supplied by the PiJuice? It seems odd to me that this would be the case. The options I see available seem to rather enable shutting off power to the PiJuice specifically, leaving it on to the actual Pi itself. Am I correct with that assumption?
Would the micro-USB power input on the PiJuice provide such a shut-off option instead? If so, I guess I'd be better off switching around the 2 USB plugs to start with! If also not possible, I'll have to look into adding an external switch system that I can trigger with the IO pins.
Curious to hear your thoughts!
K

[kurijn]

I've figured it out in the mean time, so I'll share it here in case it is of help to someone else.
Having studied the related sections in the hardware and software docs, I made this diagram

So, shutting off power from the Pi USB (/GPIO) entirely is not possible as the PiJuice can only switch this power on/off to itself.
However, there is some sort of total control over the micro-USB of the PiJuice itself. While it cannot be shut off completely (only lower amp control), it will be shut off completely if the "precedence" feature is set to 5V GPIO and there is a USB connected to the Pi. So, I could work with that.