If you’re going to have an outlet installed in your garage then the NEMA 14-50 is the most common. This is what Tesla started using and what all others have followed suit with too. Not to mention the cable that comes in the XC40 has a standard 120V outlet and a 240V NEMA 14-50. So the latter would be ready to go. For new users reading this, my suggestion is having a NEMA 14-50 outlet installed in your garage (make sure its ~20 feet or less away from where the charge port is on the car). Expect to pay $200-300 for this install, but that can be much higher if the run is more difficult (ex: detached garage, or garage is very isolated from your main electrical panel, etc).
RE: The Charge Point Home Flex — its a great unit, for sure, but its a bit overpriced. For the $699 price tag, there are cheaper options. That said, if its free, it is a fine unit. And the reality is that if you get the NEMA outlet installed at home, then the cable that comes with the car is adequate, and what many/most people use in the EV. No need to spend $500+ on a permanent wall unit if you don’t want to; but having so does provide more robust longevity. Also worth noting that if you really wanted max charging, getting a 60A breaker and a 48A EVSE on the wall would provide even faster charging, as I believe 48A is the max the XC40 can allow. Ciao!