Making changes under 'Settings->Configure Toolbars' corrupts the menu system. The 'Go' and 'Settings' menus become 'No Text', 'File->Quit' and all 'Configure' items under 'Settings' are removed. Deleting ~/.local/share/kxmlgui5/kiten/kitenui.rc restores the original UI configuration. Examining the bad kitenui.rc file shows that the <Menu> tags all gain a noMerge="1" attribute. Removing this attribute restores the menus. Reverting kiten to version 22.12.3-1+b1 fixes.
I have filed a bug upstream as well: https://bugs.kde.org/show_bug.cgi?id=498442