This is also another thing I love about this manga. That yes they use the premise that he's an idiot in studying and sports. And yes they are sticking with that trope with him. But it's not like he's not doing anything and accepting that fact, he's making his own improvements to do better and trying. There's development in him actively working on it even if at the end of the day, his scores aren't going to affect his life after ReLife. And it's what makes reading so satisfying because you just want to root for him (and of course other characters who are improving their flaws) to succeed.