As the title implies, I do not have an “Online Accounts” section in my system settings on my Kubuntu 24.10 install. The only entry I have under “Networking” where I think it should be is “Wi-Fi & Internet”. Tried Googling around, and while I see more people who have the problem, no solution yet. Some stuff I have already tried in no particular order:
Just checked on my install a Debian testing based KDE 6.2.4 it was not there either. Checking the packages you mentioned two were not installed. Here is the installation of them and the packages they pulled in, after this the online accounts appeared in the Networking and if I wanted it appears to allow me to setup up an account. Check to see if they are installed on your system, particularly the qml6-module it should be the one responsible for giving you the system settings displayed option.
I think this may be an issue with Plasma 6.1, or at least a transition between Plasma/KF/Qt5 and 6 components. Kubuntu includes the online accounts packages by defualt
The packages set is different, as most of the ones with “6” don’t exist in 24.10/Plasma 6.1, but others that seem to be similar are present.
I just found an old neon iso with 6.1.x, I might check it out and see if it suffers the same fate as Kubuntu and/or compare packages