I couldn’t get into Roberts, I liked the basic idea of On but I can’t say I liked anything else. Salt was the same deal, really cool concepts but the rest didn’t stick
Charlie Stross maybe? Not a fan of his space opera stuff, but the Laundry might be ideal for you, probably a good match for the PC Grant stuff. Faint recommendation from me but others love him
(to his great credit, I accidentally once told him to his face I thought Singularity Sky was shite, he took it incredibly well. That was a total setup, and I’m reasonably sure that it was Hannu Rajaniemi that did it to me, which leads me neatly to recommending the Quantium Thief- which is kind of Locke Lamora In Space. Very challenging writing style though, he seems to take pride in incomprehensibility, I don’t really appreciate that… But still well worth the read. Reminds me of Lord of Light, and of the Culture in general. But always feels a little bit like you missed a page)
Also, Flowers For Algernon, everyone should read Flowers For Algernon. And Stand On Zanzibar.