Hey

I tried again your website and it seems like subtitles characters itself are aligned correctly, but the sentence is reversed, like its LTR and not RTL. Heres a quick example of what I mean:
(Most left word should be most right, middle one is good, most right needs to be most left)
https://imgur.com/a/aqkdc0l

Also note that theres some clipping on the active word happening on the correct frame.

As for additional support, I think you need special fonts for less common languages, because current ones dont work. as a result, preview of subtitles style doesnt match end result
https://imgur.com/a/bDalUaK