It would be great if we could hide the read messages from [[Special:Notifications]]. This could be the default behavior, and a toggle button could allow one to show the read messages when needed. Such a change would make the special page to behave more like LQT's [[Special:NewMessages]].
See also T97057: Visiting Special:Notifications should not mark notifications as read
Context from T93109: T1. Convert unread LQT notifications into unread Flow notifications: