It's not like it's mindless drudgery either. Losing as little as possible in translation while fitting within the constraints of subtitles (people can only read so fast) can be very challenging. And decent dubbing tries to approximately match the mouth movements, which puts further constraints on the translation and often requires creative text changes.
There is a point about industry size (not that many countries dub all their movies), but it is one of the intellectually more challenging professions.
Translation work is often associated with horrible working conditions and poor pay. It definitely fits OP's description of "jobs that crush the human spirit into oblivion." This might not be the case if you're a renowned translator of famous literature, but that is not representative of the majority of translators.
It takes a fluent, language specific bilingual with domain knowledge just to verify work. That's a high skilled job. It's just massively underappreciated because (same).
Voice acting (dubbing) is acting, which is a "high form of labor". In some languages/countries, most of the dubbing is performed by a few extremely good voice actors.
LLMs aren't going replace all actors or all voice actors just as they won't replace all illustrators or writers.
LLMs provide a certain level of mid/low quality content in nearly all mediums. And given that there many people producing such mid/low quality content today, LLMs will have an impact. LLMs affecting sales writers? Sure (not the best sales writers but the point is sales is mediocre but acceptable is a norm).
And say LLMs specifically. There's good evidence the technology has roughly peaked. That doesn't mean it's impact has peaked but it's indication that "all jobs at risk" might be an exaggeration.
they wont replace voice actors for that. Rather it will replace voice actors for niche languages for niche content. Just like AI generated images doesnt replace artists working on the latest pixar movie but rather lets some small blog ad an image they would never had otherwise.
But there's a lot of people who have been working as voice actors for small/medium visibility content. Toothpaste ads, Kickstarter promo videos, corporate training videos, mid-range video games... a chunk of that is going away, and it's going to hurt a bunch of people who were previously able to make a decent living off it without being a star.
In which country? Germany and France put some effort in and it’s still not great most of the time but most languages dub only in 1 or 2 voices for all characters. Just look at the ridiculous long credits of Netflix shows.
Brazil has a long history of dubbing, not only translating but also localizing tv shows and movies. In some cases the shows are actually better dubbed, because the voice actors are better at emoting than the original cast.
Anime dubs from Japanese into English are often quite good, even idiomatic (I am sure there's some license taken, say for something like <<Kill La Kill>>, but the overall result is much better for it).