I can see both viewpoints here and don’t have a strong personal view
But for reference browsers fire the keypress event on keyup
The keypress event is an ancient mistake that I think never had any legitimate use case, and has been deprecated for quite some time now.
> If supported by a user agent, this event MUST be dispatched when a key is pressed down [...]
https://w3c.github.io/uievents/#event-type-keypress