Collabora Office. It's a free LibreOffice fork for iOS/iPadOs. I stumbled across it when I taught regular expressions to my pupils and only had MS Office at hand, on the school computers, which is crap at searching for pattern matches in documents. Libre Office is really good at that. And all my pupils have iPads and they could use Collabora Office.

yunohost it's basically an os that easily lets you selfhost, by having an extremely big amount of selfhosted services packaged with scripts that autonatically set everything up and all of that trough a clear and modern web interface.