And if you need it in a browser, there is Collabora, which exists as a paid business version with support or a free non-support version, that can easily be deployed with Nextcloud. Another alternative would be CryptPad.

If you also need your mails in your browser, there are multiple providers like mailbox.org that offer mail encryption even through the online mail interface.

Thank you for your amazing posts! I really enjoy them!

The magic key for me is to tell no one about my project, until it’s in a workable state. Just telling someone what I want to do, including the details of my plans, is sometimes enough for me to never actually start with it. But keeping it quiet—which is very hard mind you—leads to me actually acting on my plans.