It feels rather rude to the volunteer developers to accuse them of enshitification. Especially when it's not even true in this case as enshitification implies trading the user experience for shareholder value - there's no share holder value being extracted here. The developers made the decision based on its merits. Furthermore, as I remember KDE4 did still have Konqueror - though it became slowly less maintained throughout its lifecycle as the web browser bit was hard to maintain in the changing web climate and Dolphin was providing a good user experience for many users.
They traded user experience for developer egos. Ego is the equivalent of wealth in the OSS world, just as it is in academia. KDE 4 developers had some grand ideas to push on the world, such as the semantic web, regardless of whether or not their users cared for them.