Full disclosure, this is basically a copy/paste of what I posted to the Squid Game subreddit, but it applies to any show. Netflix is a goldmine of media that one can use to get fluent in any supported language. I use it to learn Japanese so these tips should apply quite well here.

Tell Netflix you want Japanese media options - Go to "account settings" in the top left pull-down menu. Scroll down to your account and expand it so it looks like this. Click on "change" which shows two settings like this image. The top selections are for your interface language (I use English). The bottom selections are key as these show media that have some form of that language option available. The third last selection checked is kanji for Japanese so make sure that's selected as well as your native language.

Now if a show has Japanese audio or subtitles it should be shown to you even if your native language is not supported. Well that and if regionally it's allowed in your location.

Language Reactor This is a Netflix Chrome Plug-in that leverages subtitles and audio to help with language learning. If you're not aware, subtitles basically are text files with a sentence, start time when it's displayed, and stop time when it's removed. In most cases, this corresponds with the spoken dialogue of the same line of text. What LR can do (lots of choices based on your personal preference) is blur subs till you hover over them, show you translations of individual words, show you two subs at the same time, show machine translations (usually DeepL), save sentences or words, show text frequency, etc. There are even options to output the subtitles into a transcript format.

Note that if you have other Japanese videos not on Netflix on your computer, consider using MPV Video Player that replicates the above in addition to other techniques.

Compact Immersion Audio - There is a program called Chidimeru (I can't link to the media fire as Reddit automatically removes those, but you can look for it) which rips the audio from your Netflix show which means you could listen to your Japanese show while you're exercising or commuting. However, it does one additional thing which is remove long pauses in dialogue when there's no talking. This takes out music, montages, and long staring silences that may be useful for watching the show but not necessary when listening to it for Japanese language immersion. For Terrace House this means long music montages (usually in English) along with the opening/closing credits are removed creating a 15 minute audio file of discussion in Japanese.

Immerse in Japanese from the Start Try these steps: Watch every show you can in Japanese, even the non-Japanese shows. Just turn on the Japanese audio. Watch each episode twice: once with Japanese audio w/ English subtitles (or whatever is your native language), then once more with no subtitles. The first watch makes the episode comprehensible (thanks to the subs), while the second watch in full immersion in Japanese with a comprehensible show.

The Reason Behind the Madness A mistake many new language learners make is not watching shows in the language they're learning. They think they need to learn the language first then watch shows. Another is they keep watching shows in their native language meaning that time is not benefiting learning or acquiring a new language. Yet another is watching with English subtitles all the time. All of these mean you're not listening to Japanese aka not immersing.

Personally, I've watched Terrace House in Japanese, but I'm also watching BoJack Horseman (or Squid Game, or Titans, or Avatar: The Last Airbender) in Japanese as well. They're non-Japanese shows but they're still fun to watch with the Japanese dub. Hell, personally I think the Japanese voice actors for BoJack Horseman are better than their US counterparts.

This Is Immersion, not Studying What should happen if you keep up this immersion is it'll complement your structured Japanese studies. As you learn more Japanese through study you notice that used in the media you're immersing in. Over time, you might find you're learning more natural Japanese from shows than you could ever learn from a textbook alone (or at all).

PS: In a few weeks, I'll be doing a "Let's Read Terrace House: Boys and Girls Next Door" as my 33rd Let's Read Japanese series. I'll post an update here when those are published.