Google RCS and RCS the standard are not the same thing. Third party apps are not allowed to plug into Google RCS. This is why you won’t find any RCS open source alternative for Google Messages.
Google is just trying to promote their own walled garden under the guise of an open standard. If they were genuine about this they should allow you to just use any replacement, just like you can replace the stock SMS app on Android.
Movies are a great way to learn a foreign language and subtitles work wonders to increase reading speed. Especially when they don’t give you a choice to fall back to a dub.
Source: me, having to watch Cartoon Network as a small child with no translation at all, became proficient in English by the 5th grade in a country where English is not spoken at all, other than when being (poorly) taught at school.
So rather than seeking out dubs you should avoid them as much as possible.