Not really! You can find the source code for almost everything in their github (I say almost because I haven’t checked if everything is in there, but I know the clients are because I’ve looked them up). Besides, aside from offering extremely competitive prices, they are privacy friendly (don’t offer end-to-end, but you can read their privacy policy) and use a very ethical infraestructure. I seriously recommend you check infomaniak up; I have been using them for 2 years and couldn’t be happier.

It is already open-source. All of the source code is on their github and, for docs, they use an implementation of onlyoffice very similar to the one in Nextcloud