If there is no accident then Real Madrid team will dominate La Liga next season too. Madrid's squad has not been very strong this season. Vini and Rodrygo's performances were erratic. Even then, Ancelotti's mastermind led Real Madrid to win the La Liga and Champions League titles. Mbappe joins the squad to strengthen Madrid's squad for the coming season. Mbappe will further strengthen Madrid's attack.
On the other hand, Barcelona's situation is now very shaky. The performance of the players in this team is erratic. At the same time, Barcelona need new players to strengthen the squad. And Barcelona can't afford to play any new players right now. So it is unlikely that Barcelona will dominate La Liga next season.
I don't understand what you mean by Vinicuis and Rodrygo performance was not good this season, Vinicuis and Rodrygo are the top players of Real Madrid this season. I agree that Rodrygo performance was not as good as Vinicuis this season, Rodrygo made many mistakes, and missed a lot of chances they could have convert into goals. Vinicius on the other hand, if he missed the chance to score his first goal, I believe he wouldn't miss the second chance to score. If it were not for the contribution Vinicius made to the club, I don't think Real Madrid would have been able to win the trophies that they won this season because it was only Vinicius who had speed in Real Madrid that disturbed their opponent's defense. Mbappe joined Real Madrid to strengthen their squad and win more trophies next season, not because they had a bad performance this season.
In addition, we know the issues going on with Barcelona right now, their performance was very weak due to the injured players they had this season, I will not expect Barcelona to dominate La Liga next season unless they add more players to their squad. However, the Barcelona president stated that they don't have to sell any of their current players to acquire more players to the club, and even though their current players are fit to play next season, no way for Barcelona to dominate the league.
when benzema was at real madrid a few seasons ago, whenever he got injured real madrid lost the game and had difficulty scoring a goal, see that Vinicuis and Rodrygo were playing and even so real madrid couldn't do well without benzema benzema, that's why the Real Madrid coach brought in Jude Bellingham, who was Real Madrid's savior in the season that recently ended. It's true that Vinicius did well this season, but he was still surpassed by Jude Bellingham who scored 19 goals in 28 games and made 6 assists, and see that Jude Bellingham's position is average and even so he had better results than Rodrygo and did better than Vinicuis in La Liga.
If the Real Madrid coach hadn't hired Jude Bellingham, then Real Madrid wouldn't have achieved anything this season, most of Jude Bellingham's goals were decisive in the games, while the majority of the goals scored by Vinicuis didn't decide the games, They were goals that didn't make much of a difference. By that I mean that Real Madrid needs Mbappe, because they don't have a striker of Benzema's level when he was at Real Madrid and Mbappe can very well replace Benzema's place, Joselu, despite having managed to score goals in some games that They decided the game, but it's still not at the level of Benzema and Mbappe
I agree that Vinicius is an excellent player and that he has done well this season, but he is not a player that Real Madrid could afford to let go of Mbappe and no longer use Jude Bellingham as a striker just to have Vinicius, If the Real Madrid coach did that, then Real Madrid wouldn't score goals and they would lose games.