I would like to point out that the people complaining “why doesn’t their clothing look medieval? D&D has to be medieval!” are taking a very privileged and Eurocentric position. Zinda, the setting for the Wages of Vice adventure that this art comes from, is based on African American life in the southern USA (specifically New Orleans) as well as Gullah/Geechee folklore. Godsbreath, the setting of Written in Blood, also draws from African American life in the American south. Non-medieval clothing is also present in that adventure.
One of the goals of the Radiant Citadel book was to explore the lived heritage and experiences of a variety of ethnic groups that aren’t often represented in D&D or other fantasy media. There are many ethnic groups that were the product of post-medieval European colonialism via forced migration, slavery, and mingling of different groups. Millions of people were stolen from their homes, sailed to a different continent, forced to speak a different language and practice a different religion, and enslaved and discriminated for centuries. African Americans are a people that are in many ways divorced from their ancestral lands, religions, lifestyles, languages, and pre-colonial history. Of course the adventures drawing from their experiences aren’t medieval. African Americans did not exist in the Middle Ages.
To complain about this art because “D&D has to be medieval” - which plenty of official settings aren’t (Dark Sun, Eberron, Ravnica, Theros, Ravenloft, Planescape, Spelljammer) - is a form of ethnic gatekeeping. It’s proclaiming that certain groups of people aren’t allowed to use their own history, experiences, and folklore for inspiration for their D&D games because you don’t like the vibe or aesthetic.
It’s really weird to me that some fans have determined that they get to decide what D&D is allowed to look like and therefore which ethnic groups are allowed to use their history and experiences in official books. I would argue that the fact that Journeys Through the Radiant Citadel didn’t feel constrained to being medieval is one of its strengths.
I would also like to point out that there is an adventure in Journeys Through the Radiant Citadel based on medieval West Africa; Gold for Fools and Princes. It involves a gold mine and aurumvorax.