How “credited as” field should be filled in case if it is multilingual credits? (example in the screenshot above)
Should it be:
First: The purpose of “credited as” is to give the version of the artist’s name used on the release. The “translated and performed” phrase should not be included; that should be handled by adding two relationships to the recording (one for “translated”, plus whatever performance relationships apply). If you’re creating this as a release (as opposed to a standalone recording), it’s generally easiest to add these from the “Edit relationships” tab after creating the release.
Second: One name or both? I don’t see a specific guideline for this, but from what I’ve seen it’s (more or less) expected to use a single name here, and I’d be inclined to use the first name listed.
You can instead document the multiple versions of the name in the artist’s aliases tab (example), though it looks like that’s already been done.
in addition to the above, you could copy the credits as-is to the release annotation, in this case just what’s in the screenshot you added
@d7b8w0f8 @UltimateRiff Thanks to both of you!
Of course I know about artist aliases and always add them. Maybe, I even of the most active users of them 
Which formatting would you use?
I’d just copy it as-is, maybe put it under a header like === YouTube credits === or something. this is pretty common for text credits from Bandcamp, and I’ve even done similar for some physical CD releases too (just the credits tho, I wouldn’t copy the whole of the liner notes or video description as there might be copyright issues there)