Rise - Language and labels editing

Hello,
I have two questions regarding labels and course language.

First, the language - I'm making course in my native language (PL in this case). I select labels for my language in rise course process making. It works almost as it should - my labels are (mostly) polish in published course.

However, the html lang is set to en. I rememeber that changing this by hand to lang="pl-PL" solved the problem earlier. Now it doesn't work. I've found in the main.bundle.js file that this is now dynamically updated from label "iso639Code". That's the issue because for example Chrome automatic translation is based on this, so I'm getting a notice that I can translate my polish course to polish from english.

And now we are moving swiftly to second problem (which will solve the first one) - the labelSet. Labels are set when making course in rise, that's why most of the course is properly translated (like buttons, lesson x of y etc.). Labels are stored in three places:
1) The default, english ones inside main.bundle.js, I guess in case something goes wrong.
2) In plain text inside index.html, in window.labelSet
3) In encoded base64 text in window.courseData - and that is the set that is used by default.

Now my question is, if you don't want to dig deeper, can you make Rise use the window.labelSet plain text instead of the window.courseData labelSet?

Now to elaborate more:
The 3) labels set is being used by default. That means, if you change something within encoded base64, it will occur inside your course. For example, you can decode the whole courseData, change the iso639Code to "pl-PL" in that decoded output, encode it again, replace inside index.html and woosh, the course has now proper lang="pl-PL" (for my case of course).

But that's neckbreaking, if you need to do it for every course. And also, you can notice I wrote "my labels are (mostly) polish in published course" - because some of them are not. For example, aria-labels for Accessible courses. Take the Video player explaination - it is written in english, in case 1) 2) and 3), and you cannot change that when producing course on Rise platform. You must decode the courseData and change that inside labelSet. Man, that's a lot of time and there's high chance that you will make a mistake and break your course.

So my idea is simple - make Rise use 2) instead of 3) for labels. You can change labels in plain text, which is easy for even beginner user. Can this be somehow achieved?