What happens when you disconnect the battery?

Numerous people have suggested I use a battery disconnect to resolve my parasitic drain problem.
Here's what happened when I didn't drive the car for 3 days, and the voltage fell below 5V:

Here's an excerpt from the email I got:
The primary driver for the 2024 Toyota Prius Prime XSE has been updated. The vehicle has been removed from your Toyota account and any active subscriptions, services, and reservations have been cancelled. If applicable, any Digital Keys or shared Digital Keys for this vehicle have also been disabled.

When your vehicle was removed from your account, by default the vehicle was reverted to Privacy Mode where a limited set of data, including location data, remains transmittable when you press the SOS button in your vehicle and to enable Safety Connect features (includes automatic collision notification, emergency and roadside assistance, and stolen vehicle services). For more information, please refer to the Connected Services Privacy Notice.

I had to call the Toyota support line, and now I have a job ahead of me to sign back in through the app.