[saubeidl]

I'm not sure about Nextcloud, but the French government built a thing that looks pretty good: https://docs.numerique.gouv.fr/home/

If you want a full suite, the German government has been working on integrating and packaging a whole open source productivity stack: https://www.opendesk.eu/en

[mschild]

I applaud both efforts but openDesk is mainly aimed at governments and usually only implements 3rd party OSS.

Their file storage solution is Nextcloud, chat is element, etc.