To me the "opendesk" effort looks like a lot of not-open source "licensed" software ("with less than x% closed source") and a handful of wrappers around other people's open source software (diagrams.net wrapped as cryptpad, for example). In fact they recommend the "enterprise edition" which is NOT fully open source, right?
It says all the right words and has a flashy landing page, but doesn't seem very open or impressive; am I wrong in my assessment?
In my understanding it is fully open source and it's source code is available on OpenCode [1]. OpenDesk use nextcloud, Open-Xchange, Element and so on. And it actively contribute to this software. In my understanding, the enterprise edition, is the non-self-hosted version of [1].
What is the not-open source software used in OpenDesk? Because your example: cryptepad[2] is GNU Affero General Public License. And diagrams.net might look similar, but also LibreOffice looks similar to MS office.
[1] https://gitlab.opencode.de/bmi/opendesk
[2] https://cryptpad.org/