Use Dolphin from Kde5 in Kde6
After upgrading kde plasma from qt5 to qt6, bugs were found in dolphin. For example, Dolphin Service Menus is missing. So I copied the binaries and libraries from qt5 that disappeared in plasma6 and created a deb package of dolphin.
Additionally, for better display of the Dolphin icon on the taskbar, you can download archive applications.zip and move its contents to the folder $HOME/.local/share/applications/.