I’m a subscriber & I actually noticed this also.
I have sites in Japanese. The site language is in Japanese, no plugin required to do this.
For me being the admin I can select in my profile to have the admin & site (-minus Japanese content) completely in English.
This is the only plugin that I have that is taking the admin language from the site setting instead of the admin profile.
I also would love for the “admin panel” to be based on the user setting & not attached to the site setting. If there was a way in the backed to change the language that would also help.
Currently only this plugin backend is in Japanese.