Is the iPhone 5s a vintage device

See the list and information in: Obtaining service for your Apple product after an expired warranty - Apple Support

You have to define “vintage”. It is still a supported device, and is still being updated with security releases. The current iOS version for it is 12.5. It cannot be updated past iOS 12.x, however.

Well, that model was released on September 2013 and its production stopped on 2016.

Regards

Giulio