blindsight was cool, its sequel was not as good but still worth a read.
greg egan probably writes the hardest sci fi that i'm aware of, and usually tells an interesting story. his early books are more "accessible", any of pic related are good to start with.
his later books almost feel like a physics course in some alternate universe, e.g.
https://www.gregegan.net/ORTHOGONAL/00/PM.html 
