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
Last time I checked (about 2 weeks ago) you would have to build it yourself, I don’t think they distribute precompiled binaries yet. (Although what I did try to replace were the Desktop Editors, not the Android app) Also, I see no reason why it shouldn’t work in Canada, I believe the reason it’s called that is just because it’s being developed with European organisations in mind.
I don’t see a repo for an Android app. (I have made an open issue request about it.)