In honor of the new ISO release (and because I like to fresh install for the heck of it!) I did a fresh install of the Online Installer with Plasma, making sure all the check boxes were activated. I had two significant headaches after the install that I had to spend some time working out. Following is for others to hopefully find helpful:
Firstly, khotkeys is no longer installed by default, preventing creation of custom shortcuts. (Among others, for some reason Keepassxc cannot be assigned a shortcut in the usual way.)
Secondly, several plasma widgets that I use are not available in the default install because kdeplasma-addons is not installed. Among them the Application Dashboard, Weather and Sticky Notes widgets.
I spent some time hunting down the above solutions, so hopefully someone else will save some time.