You can use the ogg=true url parameter when downloading a file from your library.
curl -s http://[teddycloud-ip]/content/test.taf?ogg=true&special=library -o test.ogg
Another option is to use opus2tonie. This is also possible with my container.
docker run --rm -v $(pwd):/data ghcr.io/marco79cgn/audio2tonie opus2tonie --split "/data/test.taf"
This way the taf file will be split into one ogg file per chapter.