I recently watched Project Hail Mary, and... I didn't hate it... but I didn't think it was great. I read the book back in 2022, and I disliked the book too.
It got me thinking about "millennial writing" people bring up often. I guess Weir isn't a Millennial, but I feel like his writing style matches it closely. Actually, maybe it should be called "gen x writing".
Anyway, most people know the basics. Characters never take anything seriously, they are always cracking one liners, women are placed in prominent positions of authority for some reason, etc. The main character is a man, and is a goofy chungus who is smart, but not smarter than the women around him. A big one that I've never seen anyone address though are the tendency for overly detailed technical descriptions, usually as a way to make the author feel smart.
His first book, the Martian, gets away with it, since the entire book is about this guy stuck on Mars, stringing everything he has together to survive long enough to be rescued. It was an interesting concept and it fit the narrative. Hail Mary has a lot of this stuff too... and it just doesn't fit. I don't need details of Ryland Gracling making a pendulum to determine the acceleration of this spaceship he's on, he could just look at an instrument on his ship.
But I don't think this is a "Weir problem", I've seen this everywhere. It's obviously very present in "isekai" and "self insert" stories, and it's everywhere in fan fictions. A lot of gen x authors and onward have totally abandoned "magic" in stories (a supernatural force that can't be explained logically) for magical realism (physics of non-existent physics). This can be interesting, but when it get applied to everything constantly, it gets boring.
The cutoff for this really does seem to be between the boomers and gen-x.