In the linked Nextcloud blogpost, the CEO of Nextcloud is quoted saying they would put full support of open standards like ODF “on top of the agenda” for the next release (after working on the desktop and mobile apps and integration features (maybe for this release)?).
OnlyOffice and therefore EuroOffice does not support ODF natively. It can only be converted to Micrososft’s OOXML for viewing or editing: https://helpcenter.onlyoffice.com/docs/userguides/document_editor/supportedformats.aspx
In the linked Nextcloud blogpost, the CEO of Nextcloud is quoted saying they would put full support of open standards like ODF “on top of the agenda” for the next release (after working on the desktop and mobile apps and integration features (maybe for this release)?).