They are still expressing the joy of achieving a new history. Let them enjoy it in their own way, however, they are looking forward to it with a lot of effort and money.
Every team that will compete in the Champions League will definitely update their performance for next season. The new season will definitely come with new competition. PSG will definitely still realize that they have not dominated in Europe, they still have to fight hard for next season.
PSG got a golden opportunity this season especially after seeing top European teams getting eliminated one by one due to their instable performance, otherwise PSG bosses are more than aware that holding the Champions League title for another season will be mission very hard.
I suppose there will be some movements in the team but not that drastically change like the others. Real Madrid especially will have a good update and will be the main threat for PSG ambition.