As long as Real Madrid doesn't have any problems like Barcelona is currently experiencing, they will continue to dominate every competition, including the Champions League. Real Madrid is the club with the most ambition to win every trophy, they will continue to improve the quality of their squad to dominate other clubs. Real Madrid success in winning the Champions League and La Liga trophies will probably continue next season; they are still strengthened by the players who won trophies this season. Mbappe arrival will also have a big influence on Real Madrid performance in the following season.
Several other clubs are experiencing internal problems which are causing their performance to decline slightly, Barcelona is experiencing financial problems, while Bayern Munich is adapting to a new coach who has minimal experience in European competitions. Only Manchester City is the toughest competitor for Real Madrid in the title race, Leverkusen may make a surprise next season with its increasing strength after bringing in new players in the transfer market.
I agree with you that currently it is only Manchester City that can be a challenge for Real Madrid because in the Champions League competition, but for the next season, I believe the Champions League will be a hot competition. Arsenal will also bounce back, although there are many teams that will not be able to compete next season, and seriously, Real Madrid will have a strong season next season because of the signing of Mbappe. For Bayern Munich, I don't know of the Bundesliga competition, but as for the Champions League, they will experience a hard time next season because their new coach is coming with a new method of play. that they need to get used to before their performance gets better.