Of several teams such as Al-Nassr, Al-Hilal and Al-Ittihad, the news that was loudest about joining Al-Nassr was because Casemiro was so close to Ronaldo. I think if he is on the same team as Ronaldo, it will give Al-Nassr someone who is experienced in midfield and that will help Al-Nassr achieve its target, namely winning the Saudi Pro League next season. Apart from that, Casemiro's big name, who often wins the Champions League with Real Madrid, will certainly make this league even more popular.
SourceL https://twitter.com/FabrizioRomano/status/1810053111987208456
I think Casemiro going to the Saudi Pro League is good for both parties involved, i.e the club and Casemiro himself. His performance in the Premier League declined heavily, and he faced a lot of criticism. Comparatively Saudi League is much less competitive than any other league, and the state Casemiro is in, he will still be able to offer a lot of good services to the club he goes to. Watching him alongside Cristiano Ronaldo at Al-Nassr will be a joy for all of the Madrid fans to have a look at. And apart from all of that, Casemiro's injection into the league would make it a much better place as a whole for sure.