I only watched the trailer of Project Hail Mary (that title!) and it looked like a movie for a very young audience. I actually liked The Martian when it was about ‘How to survive on Mars’. The moment it was all about the rescue mission (“Let’s bring him back home, guys”), I was bored to death. It was Gravity all over again.
Yes, the rescue part of it is not my favourite. It’s okay. And that last act is very tense, wouldn’t be without it. But I do agree that the appeal is in the Robinson Crusoe aspect of him being alone and trying to survive.