If official original booklets specify pen names for work credits we should use that.
As artist credits (AC) most of the time, not necessarily as another artist (this was necessary before AC existed).
There was probably discussing in the old forum, but here, with a “pen name” #musicbrainz search, I found Is there a preference for legal or performance names in writing and performance credits? which itself links to another previous topic Performance Names and Legal Names in regards to works.