Hi,
and here a solution for these who are also missing the "Extract here" within dolphin. Seems like the initial approach of symbolic linking against the service desktop files provides by ark was basically the right approach. However for some reason it seems that also the "konqpopupmenuplugin.desktop" is missing for kf5. Thus the menu was not appearing after all.
So in order to fix the issue, simply perform the following commands as root: --- ln -s /usr/share/kde4/services/ServiceMenus/ark_* /usr/share/kservices5/ServiceMenus ln -s /usr/share/kde4/servicetypes/konqpopupmenuplugin.desktop /usr/share/kservicetypes5/ --- Then perform a "kbuildsycoca5" as user. I hope that I not having some other "fixes" in place as it took me pretty long to get this running. So would be nice if someone could confirm that the above description is really enough to fix it. At least here the ark menu is there and seems to be working fine now. Not sure what official package this might go in order to fix this.
Best regards, Florian