In our Nextcloud we already have Collabora Office activated to manage all kinds of documents (Open Document format and also Office XML). This is really good since Collabora Office is endorsed by the LibreOffice community (for example by Italo Vignoli).
The problem is, especially from macOS users, we received some techical complaints about the opening of documents with Collabora Online. For example, since Collabora Online is a kind of "tile viewer" of the LibreOffice backend, I've seen that some "normal" presentations are not rendered correctly in Chrome on macOS. Literally you see blank tiles, and you do not see your contents, especially after interacting with the mouse scroll.
While we have all the commitment to create a proper bug report to upstream in Collabora Office so to improve the situation, and while this bug is not always easily reproducible to me,
we still need to unblock our users, so that they will not use anymore Microsoft Office 365 at all costs but could use "more" Free Software. That is why the Education program proposed to adopt OnlyOffice (or Euro-Office).
So we take the best of the two. So we are trying to survive both situations and make everybody happy.
The challenge is that OnlyOffice brings some known concerns, mainly because newspapers describe it as a «Russian-based company» https://www.theregister.com/software/2026/04/02/forking-frenzy-ensues-after-launch-of-euro-office/5221537 . So, while it's supposed to be open source software and while we should have pretty much control over our software, this is still something to be kept in mind. Keeping an eye over Euro-Office or similar forks.