@CommonMugwort Yes.
A live-action adaptation is different from a novel. In a book medium, an author should of course write it in the language their target audience understands.
However, in a TV/film medium, we have subtitles. If the production was made in the 90s or earlier, it's understandable, since the tradition has been to use the audience's language. It's no longer the case for the past few years. The practice today is to use the actual language of communication… unless they have a universal translator like in Star Trek.
If one wants to listen to English instead of reading subtitles, then the OTT service, or the production, can provide an English “dub”.
Now, if it is an adaptation where the setting was changed, like Netflix's live-action adaptation of the Chinese novel #ThreeBody where they set it in North America, then obviously, it should be in American English, not Chinese.
But in the case of “Shõgun”, it was set in Japan's history where Portuguese was the primary foreign language.
If the argument is simply, because it was written in English, then Netflix's adaptation of Three-Body should be in Chinese. Or, because the audience wouldn't understand, then Shõgun should not have used Japanese at all (and the actors can speak English well).
I mean, no matter where we look at it, there is no reason why they did not use Portuguese.