… had the vision to set up our building for sustainable transport. A fast AC charger was installed (7/22kW) and a number of 15A power outlets are available for e-bikes and e-scooters…
How many units do you have? 6 floors suggests quite a lot, which means that one shared AC charger might not be enough once most cars are electric. While a minority of the building’s cars are electric, you might be fine with a shared charger as an interim arrangement and people might be good at negotiating sharing.
Later you might need more charging outlets. On the other hand, they don’t necessarily need to be all that fast. They could be 7kW max. and networked to load share. When many are plugged in and/or other building demand is high, charging could be paused or limited to just 1.5kW. As some cars cease charging and/or building demand falls, remaining cars can steadily increase their charge rates. Eventually, the last few cars can charge the full 7kW when building demand is low. The control of charge rates can be done automatically by a central control box that communicates to each charger, which in turn tells each car what current they can draw.
This sort of load management avoids the need for expensive upgrades to the buildings supply.