As far as I know, Nextcloud’s Office Suite feature is in the form of integration with a separately hosted Collabora Office, which needs significantly more resources on the server as compared to CryptPad.
FreedomBox already has a calendar and tasks app, Radicale.
CryptPad can do the following:
- Encrypted Cloud Storage
- Office Suite
- Kanban
- Whiteboard
- Polls (in development)
It currently list 8 apps at https://cryptpad.fr
A more detailed post about CryptPad.
Just to clarify the requirements, a web-based office suite is not really the need. A combination of LibreOffice + Syncthing can be used to edit your documents from multiple computers. The need we should address is real-time collaborative editing. I haven’t tried collaborative editing on Collabora Online myself, so I can’t compare it with CryptPad in this aspect.