That depends on the size of the toast, appearance and frequency. We (an MSP) used a Windows toast notification[1] to encourage people initiate the Win10 > Win11 upgrade at their own convenient time (before it gets forced down on them) - and we got a pretty high uptake. The overall feedback from both the project team and users were good: the toast was unmissable, the text explanation was clear, and the big banner image was eye catching.
a "big banner image", buttons that are required to interact or dismiss, doesn't go away on its own after only a couple seconds, and might(?) also exist in the notification center
I think it's pretty safe to label that "definitely not a toast". That's just a notification, or maybe a "non-modal alert". Toasts are distinct from those by being brief and ephemeral.
It is technically a toast, according to Microsoft. If you check the link in my previous comment, the script is using the Windows Runtime Toast Notification API, specifically the Windows.UI.Notifications namespace and the ToastGeneric XML toast template.
https://www.imab.dk/windows-10-toast-notification-script/