I’m sorry to hear you’re having a rough time, mate.
Here’s a suggestion that might help you: Read the “Black Spine” adventure, and the Sundered Regions - East of the Silt Sea. This will give you an idea of how Illithids have been implemented by others into Athas, and how Athas could get connected to bring in these other races. Several of the races you mentioned would make ideal transplants via dimensional or even Spelljammer means. That might give a fun dimension to your game…