Hello, and sorry for the delay in replying to this. Indeed we are very aware of Euro-Office as our parent company XWiki has been involved from the inception of the project. We are already contributing our insights and experience to Euro-office as we have been working with the OnlyOffice code-base for years for the CryptPad integration.
We do plan to switch to Euro-Office in future and to contribute code to the project more directly, both for the integration in CryptPad and upstream. We don't yet have a clear timeline for this but we expect to have fully switched to Euro-Office some time in 2027.