There’s a tool from Spherico that might work for you. I haven’t used it, but here’s the link and description:
TitleExchange Pro is a unique tool which makes complicated things simple and fast when juggling with subtitles.
If you ever wished to get your titles out of Final Cut Pro into DVDSP (or another DVD authoring application), as text file for a translation bureau, get titles into Final Cut Pro from another source like DVDSP or STL, or ceate a QT movie with all your Final Cut Pro subtitles without the need of rendering or just “equalize” your Final Cut Pro titles TitleExchange will be your “one stop” tool.
https://www.spherico.com/filmtools/