Grant will make it in the league, it just may take a year or two for him to truly acclimate. Coaches trust him to play smart, not screw things up in the rotation, and be the ultimate teammate. There's a reason why he usually has a positive +/-, whch says a lot coming off the bench. He understands his role and knows the best way to serve his his team. He will likely never be a superstar, but someone who will play good defense and can bring 8-12 points off the bench. But who knows, he is steadily improving his 3 point stroke.
Yes, he may have missed those two free throws, but he made a critical play to foul out Kyle Lowry and helped secure the win by blocking VanVleet's game-tying shot. I wish nothing but the best for him