I think the reason why most Saudi Pro League clubs started with signing veteran players in the past was because these players were big names in football and were globally recognized so in their attempt to make the league popular among football fans across the globe, they were going for these veteran and popular footballers instead of signing young talents that will not attract global audience to the league. To an extent, they've been able to achieve their aim of attracting global attention to football in the Middle East country which is why they are now signing young talents.
Signing Ângelo Gabriel was a good transfer deal for Al Nassr even when I think they needed to sign quality defender instead of a winger. Hopefully for the Brazilian winger, he succeeds in his new club.
I also think Al Nassr would be better off bringing in players to strengthen their defense. I don't really mind young players wanting to move to the SPL. But there are also national team coaches who have a problem with their young players pursuing a career in the SPL.
Currently, the SPL is getting more popular by bringing in top European players and it is working. Bringing in young players will increase the competition. I think it will be good enough for the development of the League.
When their League gets better, it will refute the perception of coaches who think European players pursuing a career there do not have an increase in performance.