My search for
#notetaking apps and syncing solutions has me exploring
#Nextcloud and Nextcloud Notes.
Lately I've been doing a lot in the Nextcloud web interface and the Android apps. Notes can be accessed in both the regular Nextcloud app as well as the dedicated Notes app.
Nextcloud has a Tasks app in the web interface, but that isn't part of the Android app.
But you can create checkbox-style to-do lists in regular notes.
And the Tasks part of Nextcloud is supposed to sync with other to-do apps. I haven't looked into this yet.
Overall, I have maybe 30 Flatpak apps that I'm looking at. It's a surprisingly crowded space.