While this is obviously not a satisfactory solution, it does help to some extent.
In the Hyundai BlueLink that app I am using here in the UK, ther's a section that relates to the driver's profile, e.g. uploading a custom image and other settings. So obviously this part will not work for your wife if she is using the BlueLink app with the same logon credentials as yourself.
But for most of the things that I use the BlueLink app for, the driver's profile does not matter. These are the car's status e.g. battery charge level, remaining mileage, whether the doors are locked, etc, as well as the 'remote control' part where you can send commands to the car e.g. to start the climate or start charging, etc.
So if you use the solution offered by Hyundai, your wife still get the majority of the functionality from the app.
As an example, I went shopping today with my wife, we separated at the mall, and agreed to meet at the car. I arrived at the car earlier than our scheduled appointment, so I unlocked the car with BlueLink app and waited for my wife while sitting inside the car. This application would have worked for us even if we were both using the same logon credentials.
As for the Canada app... if it's the same app for Noth America i.e. also for the US, then possibly the need to enter the VIN for each BlueLink user account (which as you pointed-out is not required elsewhere) is due to security concerns, given that in the US owners are able to use the app as a digital key, something that we can't do over here. In my case, earlier today I was able to gain entry to the car via the BlueLink app, but I wasn't able to start the car or drive off.