I think it would be better for him to stay at Wolves more one season if they get promoted, other thing who might have facilitated his transition is the fact he is playing under a portuguese manager, with some other players from Portugal or ex Porto players, who made his adaptation to England more easy.
So it would be better for him at Premier League level to maintain one more season to this without the pressure of big transfers associated to him imo, if he keeps developing than why not see next season if he is ready to step up another level, after all he will be only 22 in 2019
I always said since 2014 he was more talented than Sanches, also more inteligent without relying on the physicality of the game, so it is fair to say from the 2 he is the one who will make it, if he doesn't take wrong decisions or bad luck with injuries.