Sea of Tranquility is written with a clarity and precision that, combined with its sparseness of prose, could easily have been distancing. Instead, the wonderful writing is what enables this crystalline novel to affect as much as it does. What it's 'about' isn't overly laboured, though the big clue is the section about 'so what' being the appropriate response if the simulation hypothesis is accurate; it's graceful in the way it's both literary and science-fictional, and in the endings it gives its characters.
Interesting compare and contrast: To Paradise. Multiple time periods (past, present, future), linked narratives, pandemic and partial social collapse, preoccupation with what it means to live with meaning.