The charger uses a proprietary connector on the port on whatever junction box is used on the bike. You don’t have a choice.
I set my system up, played around with assorted settings, found out Shimano only lets you pick crank and cassette options that they currently sell FOR THAT SYSTEM. Limits some shifting choices, like no small ring and small or 2nd smallest cogs available. There are ways around it though, I would always do a connection with a PC, not any WiFi system as on an iOS device. There have been know instances where the system does a OS update via BT tries to update the Di2 WiFi unit, then bricks the system as BT is lost, then needs to go to a shop for a reinstall. I basically set my system up 2 years ago and have never touched it. It works great and I leave it alone.