5G needs to be activated by the provider - a device has to be supported by the mobile network.
If the provider just doesn't do it even if the device...
SIM cards can die - in any phone at any time.
Maybe just get a new SIM from your provider and problem should be solved
You have to tap the button left of your trigger button. Activates Google lense and shows URL, QR codes and so on.
Does not matter for the charger but might be a few dollars a year because it is always powered, even with not charging a device.