Let me state it outright: I believe you're a native English speaker, likely from the US, and you believe "foreign" means "not made in America". Am I wrong? The point is: Netflix caters to a global audience. Korean shows aren't foreign to Netflix's Korean audience. So it's very unlikely that there's a constant 10% "foreign dubbed garbage" for any given spectator.
Also, I may be wrong, but every Netflix show I've seen is available in its original language (plus some additional dub options, of course). So you never need to watch the "garbage dub".
Dubs can be done very well - see Squid Game. The voices matched the characters in both body/expression and situation. The mouths fairly closely matched the voices as well, and in some scenes you might even forget they're dubs you're listening too.
The problem is, Netflix seems to push poorly done foreign films with even more poorly done dubs way too often.
> Netflix caters to a global audience
The catalog you see is what is available for your country. Which means it's curated for your country and it's interests, and/or allowed licenses. I have no doubt the Korean version of Netflix is filled with native Korean shows/movies. For some reason though, Netflix is pushing French and Belgian movies onto the US audience, mostly with horrible dubbing coupled with already atrocious acting. It feels like a "these are cheap, stuff them into the catalog!" sort of thing... meanwhile US viewers can't watch shows they actually want, like Better Call Saul season 6...
> The catalog you see is what is available for your country
That's not really relevant to my point, is it? In any case, I can assure I can see plenty of Korean, Turkish, Swedish, etc, shows listed on Netflix.. here in my Latin American country.
Any way you look at it, the assertion that Netflix has "10% foreign dubbed garbage" is poorly phrased and probably false.