[un_pogaz]

Ah
And this is the trap you have to understand:
When you ask Calibre to sort the "Authors" column, Calibre will always, always, use the "Author_sort" value.
You have to see "Authors" as a visual value only in the GUI, but not the "real" one that will be used in the sorting, hence the existence of "Author_sort". Calibre works like that. It is not possible to "correctly" sort the "Authors" column with a different "Author_sort" value. Point. (else, I miss a Tweaks)

If you want to sort strictly the "Authors" column as you would expect from its visual, you will have to copy the "Authors" value into "Author_sort". You have to go to Preference>Tweaks>Author sort name algorithm, then set the value to author_sort_copy_method = 'copy'. After the restart, right click on the "Authors" in the Tag browser and select Manage authors, then click on Recalculate all author sort values (it will take a little while).
And then, when you ask Calibre to sort the column "Authors", this will be the result you expect.