The Saudi league is not a very big league and Al Nassr is not such a big team that it needs a super coach.
Even Saudi league isn't a big league, the clubs in Saudi have the power to attract the super coach because they have the money. If you are following Saudi league news, you must already know Al Ittihad successfully hire Laurent Blanc. I am really sure Al Nassr also can do it, they also can have the chance to sign a better coach who have the same level as Laurent Blanc.
To give you an idea of what I'm talking about, before Luís Castro became the coach of Al Nassr, he was the coach of Botafogo, which is a team in the first division of the Brazilian league. The Brazilian league is much better in terms of quality when compared to the Saudi professional league. While Luís Castro was the coach of Botafogo, I saw Botafogo playing very well, to the point that they were at the top of the league and looked like a team that could compete for the title.
Before you commented to my post, have read my post carefully?
You don't need to tell me about this, I know this very well. You must be aware that I enclosed the career history of Luís Castro. It is very clear in what teams/clubs he ever managed. In transfermarkt, it is easily to know what trophies he ever won as well:
https://www.transfermarkt.com/luis-castro/erfolge/trainer/2063.
Dude, I don't compare between Brazilian league with SPL. I also don't want to compare Qatar league with SPL. I think you know well my point, I want to say if Al Nassr can get the coaches who have the success experiences in top league such as EPL, La Liga, Serie A, Bundesliga, Ligue 1, or Eredivisie. Well, I know you will argue about the quality of Luís Castro but you can see he couldn't improve Al Nassr and get the target. So why don't to think about changing him?