Are you sure your files are being saved? There’s a long standing issue that files edited in OnlyOffice are not actually saved in the file themselves.
I’ve just confirmed this myself:
- Opened document in nextcloud onlyoffice
- Made some edits
- Saved, and closed. When I reopened the file, the changes are still reflected by the only office app.
- But when I downloaded the file, the changes are not there.
Collobora doesn’t have this issue, and I’ve gotten it working thanks to this solution