Honestly I don't know what you mean "productive". I personally use Kontact suite and it is "productive" for me. I can't assume however whether it will be "productive" for you as well or not :\
sudo apt update && sudo apt full-upgrade -y && sudo apt update && sudo apt --fix-missing install && sudo apt update && sudo apt --fix-broken install && sudo apt update && sudo dpkg --configure -a && sudo apt update && sudo apt -f install && sudo apt update && sudo apt install -f && sudo apt update && sudo apt autoremove && sudo apt update && sudo apt autoclean && sudo update-grub && sudo update-initramfs -c -k all
sudo apt install --reinstall --install-recommends kaddressbook libkf5kaddressbookimportexport5 -y
https://kontact.kde.org/components/kaddressbook.html
not related but you may like to enable/ uncomment canonical partners in sudo nano /etc/apt/sources.list and install MS corefonts and codecs/
sudo apt install --reinstall --install-recommends kubuntu-restricted-extras kubuntu-restricted-addons
This will have zero negative impact on your install. Its just qt packaged. Dont install anything else from kubuntu though.
Your case sounds very similar to mine, moved from Kubuntu recently to KDE Neon, as I would like the latest KDE elements.
Thanks for the reply,
well having two separate entries in the time grid also isn't that nice (at least for me).
I'm probably also going to export my agenda as ical and use it in combination with the Event Calendar widget in KDE. May I ask whats your workflow on this? Are you automatically exporting the agenda on changes, or how do you keep it in sync?
(btw the KDE guys also developed Kontact which I often recommend to non emacs users)
I've also stumbled across org-timeline which gives at least some kind of visual representation for durations in the agenda thus it's not exactly what I want.
It improved a lot lately, but KMail and the KDE PIM suite still could need some love. If someone is interested to help, there are tons of easy junior job to get started https://kontact.kde.org/get-involved.html