What distro are you using?
Debian quite literally calls the package “dolphin” so running this command will purge it and reinstall it;
sudo apt purge dolphin; sudo apt install dolphin -y
I know the Windows version has issues updating folders live, but on my Debian machine have not encountered such issue.
Alternatively you can purge KDE itself and reinstall everything.
sudo apt purge *kde*; sudo apt install kde-full kde-standard kde-plasma-desktop task-kde-desktop sddm -y