I want to auto-populate sort-names in meta tags as well

I would like to be able to automatically add names, etc.
entered in meta tags to sort names as well.

ALBUM⇒ALBUMSORT
ALBUMARTIST⇒ALBUMARTISTSORT
ARTIST⇒ARTISTSORT
COMPOSER⇒COMPOSERSORT
TITLE⇒TITLESORT
(e.t.c)

However, an option to ignore Unicord characters other than 1-bit characters may be necessary.

Because, for example, in Japanese,
title and sort names are written differently if they are not in English.
(If the title name is in 1-bit characters, it may be possible to synchronize them.)

I am not sure if this is necessary, but this is just an idea to pass along.
(If the name is in English, maybe the sort name is not needed.)

To copy one field to another, see the FAQs:

but does it make any sense?

If the field contents of the normal and the sort field are the same, then you can spare the effort as then the player would not sort the files differently.
Could you give an example in which you entered different strings in the normal and the sort field and the sorting result was not as you expected?

Or to cut this a little short: MP3tag serves the ID3 standard for MP3 files. Modifications in treating charactersets are vain and void if the players don't follow suit (and the standard gets updated).
So actually, I doubt that there are really problems in respect to the character sets.