We should be doing this already based off of your navigator language, specifically the intent is to auto-join all the languages you have listed in your browser languages (although seems like we should be doing that based on selected language as well, not sure why we’re not).
Can you do me a favor and open up your javascript console, enter navigator.languages and copy me what is spits out?
So when I try it on my end it’s all working as expected, From your screenshot it looks like you’re using firefox which is what I tested too. Can you try under a private browsing window to see if it works as expected for you? (That just tests that it works from a fresh state). Note that if you manually leave a channel, we remember that and override the defaults, so that’s what I’m suspecting has happened.