When right clicking on the ‘Add Widgets’ option in the right click menu, the menu loads very slowly. So was not the case in Plasma version 5.27.
The issue persists on a new user, but is absent on live usb of Fedora KDE Plasma.
Plasma Version: 6.0.4
OS: Fedora 40
I made an issue about this on the Plamsa forum, and was advised to seek help here.
Link to relevant post: Adding Widgets/Plasmoids is Slow - #9 by Tionisla - Help - KDE Discuss