He is just finished.
The difference with Messi is that when Messi declined physically, he reivented himself and became more as a playmaker; he did it so well, like the best playmaker in the world. His talent, technical flexibility and game intelligence allow him to do that.
But for CR, it's impossible. He is only a finisher; and can't excell at other roles. He isn't good at playing in tight spaces or at playmaking. His finishing and off-the-ball movement declined immensely too. Actually, I see him as a problem for his team, especially with his egocentric mentality and his only focus on his own stats above the collective play and the team's interest.
This strong squad of Portugal is under-achieving and they clearly deserve better as a team; when you see the names.