If we are talking about Atletico Madrid's chance to win a Champions League title, then I don't think it will happen in the near future.

While Real Madrid is getting Mbappe and there is a Manchester City fact too, it is really not easy to reach the title. Besides Atletico Madrid's lowest expectation in this tournament isn't winning the title. Even a quarter finals qualification is seen as good achievement.
The board are really contented with the way Simeone is managing the team. They even extended his contract not much time ago. Would he like to achieve a Champions League title? Who wouldn't?

But Atletico Madrid need to make a huge improvement to reach even the finale once again (The last time they did it was the 2015/2016 season).