Mortal Kombat is a franchise famous because its high level of violence but there was a MK cartoon for all the audiences that could be watched by children. There was a cartoon of Rambo and others about Robocop. The Toxic Avengers was also a cartoon for children. A franchise for mature audiences can be softed.
The Athaspace is totally isolated and it is desertic but these are good reasons to be used like key for a new adventure. It is the best place in the multiverse to hide some cursed artifact because nobody will visit the dungeon. Or the Athaspace can be chosen like battlefield in some multiplanar confrotation because the risk of collateral damages is lower. Maybe the D&D gods knew the risk of the Phyrexian invasion and to stop them they used the Athaspace like a firewall.
Maybe after the events of Black Spine adventure a civil war started in Yathazor, the city of calamity, or something happened and then somebody become a new dark lord and his new domain was a clone of Yathazor. Or maybe Rajaat had created a clone with the hope to be the way to return to the life if some time something happened, but this had got his own soul... and after this became a new dark lord in Ravenloft.
Or Kas the vampire suffered the revenge by Vecna in a different way. He was abducted and sent to a new domain, but this was created by Vecna, a dark domain but out of the demiplane of the dread. This domain would be like the region of Tyr, but with clerics and churchs, and Kas is repelled by all the sacred symbols of all "real" religions (whose deities haven't to be real, only faith is necessary). At least Kas feed on fiends (not only gnolls) and even he enjoys drinking blood from infernal and catastrophic dragons.
Or survivors of the cleasing war created their own "domains of delight" within the "land-within-the-wind", and from here they traveled to other zones to explore. Maybe they found an astral domain based in "Jackandors" but with visitors from other places.
Or Vecna, deity of secrets, created his own astral realm like a clone of the Athaspace. What a best secret?
* I wonder if a section of DM-Guild could be opened for titles focused mainly into art. Some profesional artists and graphic designers could use the setting to show their own creations.