Cryptpad seems really nice, but I got a few drawbacks that makes me wonder why it's unavailable.
As an example, why is cryptpad a website and not a webapp/desktop app/application, and make the hostable part only the back-end?
The need of a website makes that you need to trust 2 entities, both cryptpad.org and the server you connect to. It can't read your data, but it could send you a malicious html/js to make your browser send away your data and documents. So it removes a lot of the benefits of using cryptography to make the files unreadable even from the server perspective, since a malicious actor could still bypass that issue.
A desktop app/webapp we would download on cryptpad.org or compile ourselves would help a lot with that, as we would just have to trust the org and not the service provider too (it would only send encrypted data, the server would not send anything usable)
Another one, is, is it possible not to put a user limit, but instead just have it display the available size on disk?
