Barcelona will never be able to compete with Real Madrid in their current state without Mbappe. There are many differences between the performances of these two teams, Real Madrid and Barcelona. Real Madrid is the best performer in every tournament as well as they are performing great in their league and their performance is consistent in contrast to Barcelona but they are not performing well in all tournaments and Barcelona performance is not consistent.
Real Madrid are signing Mbappe to further strengthen their squad so that they can beat the big teams in major tournaments. The main reason for Real Madrid signing Mbappe is not to compete with Barcelona or insult Barcelona, but to improve their overall performance.
Madrid have consistently been able to compete in every title race in recent seasons and as you said, if Madrid are the best team in the league at the moment and I agree 100% with you, but when you say Barcelona will never competed with Madrid of course you should read back the history of the rivalry that occurred between the two so far in La Liga, This season we don't deny that Madrid are the most consistent team in the league but I think Barcelona are still a great team when they are able to compete in La Liga and the Champions League after all the problems they have had so far and isn't Barcelona also able to win La Liga last season even though they don't have a squad as great as Madrid?
I'm not a fan of Madrid or Barcelona, but I don't think the two teams at the moment we can compare in terms of squad quality, because after all financially both are the main factors at the moment, bringing in Mbappe certainly requires a lot of funds and maybe can strengthen Madrid next season, but we also cannot exclude if later the balance of Madrid will be disturbed by the arrival of Mbappe, Because after all it will be difficult for any team and coach to be able to manage the ego nature possessed by Mbappe at this time, besides that the arrival of Mbappe to Madrid does just only make their attack line full and make them have to sacrifice other good players later?
I don't think that any player that is performing brilliantly in Madrid would be offloaded because of the arrival of Mbappe. Mbappe is there to play his own role, and don't forget that Real Madrid like to keep good players.