I had attempted to try using GNOME Todo as my daily todolist manager and by god is it awful.

Rarely saved anything correctly
Doesn't support CalDAV
Graphically buggy

I recently helped this project https://gitlab.gnome.org/BjoernDaase/journable/ create AUR packaging, and I've started using it and it's pretty nice. Super simple (just json) and works great. No coloring or anything, which is a bummer, but I'm sure it could be added.