Hi,
APA wants the username for forum or instagram posts (https://apastyle.apa.org/style-grammar-guidelines/references/examples/online-forum-references and https://apastyle.apa.org/style-grammar-guidelines/references/examples/instagram-references).
This was discussed once here and the proposal was to add it in the first name field, i.e.
Doe||John [@johndoe]
This works fine and results in "Doe, J. [@johndoe]" in the bib list.
But the problem is with Organizations that have a single name and no first and surname, e.g. a company. Adding the username in the firstname would result in "Company, [@accountname]" instead of "Company [@accountname]" as required in APA.

I could fix this with an own csl style, but there are cases with instagram posts having more than one author, a company and a user. Then I would end up either with "Company [@accountname], Doe J. [@johndoe]" or "Company, [@accountname], Doe, J. [@johndoe]", both being wrong.

Is there any way I can reach the correct format "Company [@accountname], Doe, J. [@johndoe]"? I tried to remove the ", " sort-separator in author-bib (making it empty, i.e. sort-separator="") and add the first name as ",, J. [@johndoe]". That does work for the John Doe entry as the comma and the white space after the surname come from the first name. But I fail to add a white space between Company and [@accountname] as leading whitespaces that I enter in the first name field are just removed...

cu,
Frank