Full metal alchemist, the original not Brotherhood, was the pivot point in my opinion where dubs were superior to subs.
The main characters were all well voice acted while I admit background characters were poorly voice acted.
However I say it’s the pivot point because the in top of the main characters having good voice actors the translation included cultural context I would have never picked up on my own.
For instance it took me nearly a decade later of occasionally watching subs to find out that “ore” was rude when male characters used it to refer to themselves because I didn’t have the cultural context to understand.
If I’m willing to become fully fluent in a language and its culture dubs are superior, but I just don’t have the time for most foreign media.
Do you mean that you pivoted to only dubs? Full Metal Alchemist is generally considered one of the best dubs so I don't think it's representative. While I have an affinity for Adult Swim era English dubs, I'm 100% subs now. Even things like Dragon Ball Z's sub, which can seem very weird at first if you're used to the dub, are ultimately better than the dub imho.
I pivoted to only dubs past Full Metal Alchemist because they finally were of high quality and provided enough context that they were superior to subs for me, given that I wasn't willing to learn Japanese and its cultural connotations
Just know that many of the best anime do not have dubs or have very low quality dubs. Subs will also account for some cultural translation most of the time.
In fansub times we used to supply that cultural context as onscreen notes when it was important enough. (In most cases you'd have needed to pause to read them.) Seems to have fallen out of fashion though.
Maybe it just reached its peak with “just according to keikaku (translator’s note: keikaku means plan)”
A lot of things can be done wrong enough to make them outright silly… doesn't really mean anything about the thing itself.
The Gintama fan subs were quite good, they explained a lot