OnlyOffice appears to have removed their Android app from their repos: https://github.com/ONLYOFFICE/documents-app-android
It can still be found on an archive: https://archive.softwareheritage.org/browse/origin/directory/?origin_url=https%3A%2F%2Fgithub.com%2FONLYOFFICE%2Fdocuments-app-android
This means if you are de-Googled like me, they are no longer an option.
Perhaps coincidentally, they have also started making legal claims against the EuroOffice fork: https://github.com/ONLYOFFICE#️-legal-note
That’s brilliant. They have found a way to lock in free software. It’s good that they have shown their cards now before Europe has moved to them for being an open source alternative.
https://github.com/ONLYOFFICE#️-legal-note
https://en.wikipedia.org/wiki/GNU_Affero_General_Public_License
I think due to section 10 (see other comments) they havent actually found a way, and that’s why Nextcloud and IONOS continue to move forward.