Regarding overload and optimising cheap electricity (if there is such a thing anymore) I believe there are centralised distribution systems available that will share the power supply to where and when it’s needed, slow down or shut off the car charging during peak domestic usage hours and otherwise use power when it’s at its least expensive.
EVSE Australia is just one provider that will install such a system. There are others but not all have dedicated unit block systems. This is one instance where an embedded network may be exactly what you are looking for – the provider installs the equipment and on-sells the power at a profit and your EV owners get it on a user-pays basis.