There are still rumours that Real want to sell Vinicius as early as August, which means that Alonso still sees that there is no good link between these players, so there is no point in trying to build something further around them. Although last season I didn't notice any conflict between Mbappe and Vinicius, they worked well together and brought victories to Real Madrid
The was no "conflict" because for some good parts of the season the did not play together due to injuries but whenever they would play together, one of them would not shine as the left-hand forward side is a favorite one for both.
Joking aside, as long as PSG keep up the good work it won't really be easy to prevent them from a back-to-back title.
I don't think they will lift a back-to-back title. That is too much to ask. After getting exposed by Chelsea, wait and see how teams will come at PSG this coming season. That fear factor they had is now gone!
Maybe PSG are in their bad times. Because we have seen how well they have played in the past and PSG is one of the best teams in the world. But in the final they lost to Chelsea which is really unimaginable. They beat a team like Real Madrid to reach the final. Maybe they are in a down time now and that is why it happened.
But although it is not possible to say what will happen or not. But we hope that PSG will make themselves in a good form again. If they break down because of this loss, then they may be in a very bad situation.