I have see Errands recently (modern looking gnome app using libadwaita), available through Flatpak. It can sync with my local radical server and it also has native NextCloud and CalDav support, but in it's current state it seems not be able to filter done notes/tasks/todos.
Gnome
The GNOME Project is a free and open source desktop and computing platform for open platforms like Linux that strives to be an easy and elegant way to use your computer. GNOME software is developed openly and ethically by both individual contributors and corporate partners, and is distributed under the GNU General Public License.
Ah I think this one is meant tor the todos which I also was looking for a native client for, thanks, will check it out.
It looks very good, I started using it and like it a lot. It synchronices really nicely with CalDav, amazing, thanks again!
Glad, I could help. It is nice to see having more and more good looking (libadwaita) and robust apps these days. (:
Since Gnome 45, libadwaita got a real momentum!
I agree, I also saw that that on was written in python which is kind of cool.