Obviously it will only be a rumor that will not happen and Real Madrid and Vinicius Jr said that they rejected the offer.
From this post I understand that the player is 24 years old and he still has a higher career with a big European club.
While in the SPL it will not be able to provide a big career like when with a European club and on the other hand Real Madrid is also unlikely to let go of Vinicius Jr who is currently a key player.
The rumor does not need to be taken seriously and just ignore it.
It is true that vini can earn a lot of money by playing in the Saudi league. But perhaps his career will not go forward. Vini is now at the most important moment of his career. Vini was one of the best performers in La Liga last season. And Vinicius has a great chance to win this year's Ballon d'Or. In such a situation, there is a big possibility that Vini's performance will deteriorate if he goes to a club in the Saudi League. Because the Saudi League is relatively less competitive. And it is not sure whether Vini will be able to join any big club later.
Vinicius is certainly not stupid and greedy. Vinicius has no chance of accepting the Saudi League's offer. No one wants to leave a big club like Real Madrid for a small club just for the money. Moreover, Vini's career will be better in the future. He is going to be one of the best strikers in the world in the future, unless his performance is hampered by injuries.
A few years ago we saw Neymar leave La Liga for the less competitive league Ligue 1. PSG were the stronger team. But we don't see the expected good performance from Neymar. So Vini should never take such a decision which may harm her career.