If you want the whole house, you’ll need to crack the box to get at the phase split as it comes in.
If you want to track individual circuits, you should be able to do it outside the box. It will work with single phase at least,but not sure about dual-phase; but those are usually reserved for heavy appliances like stoves and dryers.
With a digital electric meter, I could read that out but I still have an old analog meter. But individually measuring devices is also appealing. HA allows for that. Opening the box would require an electrician and it only gives measurements per room or circuit. This may also be appealing to some.
I now look into ESP Home. I sadly didn’t found a clamp meter here that works outside the distribution box or require lose mains power but ESP has the option for clamp meters
