Similar to Project Hail Mary?

So I haven't read a book in about 20 years. When I was a kid I read the harry potter series over and over as a way to escape into a world where I wasn't bullied lol, but now I'm 30 and have outgrown those books. Anyway, I picked up PHM at the bookstore last week and I have not been able to put it down. I've got probably 50 pages left and already suffering post book depression anticipating the story ending. Absolutely love the way Andy writes so I want something similar to read after PHM! His other books Artemis and The Martian (seen the movie a million times) are on my list already, along with Seveneves (was recommended to someone else in a thread) & Red Rising (saw at the bookshop and it caught my interest). But just wanting some other recommendations! I'm a space nerd so sci fi is definitely preferred