Well, fwiw as long as Madrid will sell him for a substantial amount. Not like the free transfer they got Trent from Liverpool. But I don't think Vini will go at least not yet especially now that all the pieces of the next generation of Real Madrid squad rebuild is coming to together. Imo, he would just stay put for now, enjoy the Europe glory and when he's going older, just goto Saudi there and make all the money because Real Madrid won't match that high salary as they're not that loyal to player feelings. Even Ronaldo was let go when he asked for more than he was offered.
This is clear view on Vinicius Jr. future at Real Madrid. You believe he won't leave anytime soon especially with team doing well and building for future and if he ever does Madrid would demand huge transfer fee. And yes when he gets older he will likely move to Saudi Arabia for big salary as Real Madrid even like with Cristiano Ronaldo tends not to meet extremely high pay demands showing they value performance but have financial limits.