This isn't quite accurate. `extra/kteatime` is the modern version built against Qt6 for use with Plasma or other current DEs. `aur/kteatime1`, on the other hand, is a legacy version that builds against Qt1 and is intended for KDE 1. They're not interchangeable, and they don’t conflict. Since `kteatime1` is still functional and fills a specific niche, I don’t see a reason to delete it.
https://ibb.co/YFVPMCG3