For the strength and level of their league, they do have a fair squad, AlnHilal happens to be one of the top five teams so they are doing well domestically even if it is not beyond Saudi Arabia. One of the reasons you see then going for top European players is to enable them improve the quality of their league because they know with the players they gwt from their domestic leagues, they can hardly get the same kind of quality they will get with the European players.
Recruiting top European players is an excellent strategy, as it can significantly increase the popularity of the Saudi League. This strategy is not only focused on the short term, but is also part of an effort to build the league's image to be more competitive and attract global attention. This is evident in the fact that many media outlets around the world are now reporting on the Saudi League, especially since as we know, the arrival of Cristiano Ronaldo has been a jackpot for the Saudi League in terms of popularity.
Additionally, this will make it increasingly difficult for local players to compete. They must train harder to improve their skills. The arrival of top European players should serve as motivation for local players to prove that they are no less talented than their European counterparts.