I’m not sure, but my impression is that Nextcloud has put the focus on Collabora.
My recommendation for OnlyOffice: There is an official app maintained by OnlyOffice. This is compatible with Nextcloud 24 and has been working fine for me for years. However, for this you need a dedicated OnlyOffice installation (e.g. with Docker), which is recommended either way.
Well, i get an error with the official app maintained by OnlyOffice (probably) since the update to 24.0.1. I think it’s the update because i didn’t change much other things. occ onlyoffice:documentserver --check Error connection: Error occurred in the document service: Error while downloading the document file to be converted.
I think the app needs an update also. Would be interesting, if other get the same error.