Winning the league1 trophy shouldn't be anything a real PSG fan should be that happy about because it's like a common trophy now to them. PSG winning the UCL should make you happy with the expression of a hope to win it the next season. They are a good team and I don't seem to recognise what's stopping them from winning the UCL trophy up till now
If PSG players and coaches are convinced that winning Ligue 1 is very easy then they don't need to try hard, I don't think they would be able to win Ligue 1. As a fan, I celebrate winning the title because I know that for PSG to win, it is because they invest a lot of money by hiring good players and a good coach.
If other teams also want to win Ligue 1, they should make good investments. This season's PSG doesn't have players with a great reputation like Mbappe, but they still won Ligue 1. Now, about the European Champions League, that's very complex. In the European Champions League, there are many good teams that also make good investments, so it's not easy to win and PSG shouldn't spend a lot of money just because they want to win the Champions League.