I don't deny that Cristiano is a great player, has had a good impact on the SPL in general, I'm a fan of him too, but I don't think he's given what he should have given to Al-Nassr. No SPL title, no ACL Elite title.
CR7's impact on the Saudi League is huge, that cannot be denied. In fact, they begged him to re-sign with Al Nassr. I'm sure many of us here follow the Arab League just because he's there and many other famous players. If CR7 had left the Saudi League, it would be a fact that they wouldn't have paid as much attention to him as they do now.
To add, it's not Ronaldo's fault for Al Nassr's failure; the culprit is the management, who didn't hire a coach who had achieved great success in different leagues, including the Saudi Arabian league. You can't expect a team to win titles just because they have the best player in the world. PSG is showing this in practice; even without Messi, Neymar, or Mbappe, they're performing much better compared to when they had these three good players.
So, Al Nassr's management needs to see PSG's case as a great concrete example that the most important thing in a team is the coach. If they hire an inexperienced coach or one who has only achieved success in one league, they won't be able to handle Al Nassr well and, as a consequence, they won't be able to achieve anything great.