Important bit of information is further down in the article: OnlyOffice is Russian. I would therefore view any collaboration as a risk. It's not adequate for strategic reasons as well as sovereignty.
This isn't rhetorical. I don't know which is worse. I lean disliking Microsoft more, because jazz hands at Windows11, and OnlyOffice at least runs on Linux, but it's still not a fun position to be in.
LibreOffice and other alts definitely don't have as good of Docx compat.