Osimhen is performing well with PSG. There are several reasons for this. Firstly, Osimhen's fitness is quite good now. Osimhen is not facing too many injuries. And secondly, Osimhen is the main player in PSG's squad. And Luis Enrique builds his match strategy around Osimhen. That's why Osimhen is able to score a lot of goals. On the other hand, the coach didn't build his match strategy around Barcelona around Osimhen. Osimhen also failed to adapt to Barcelona's tactics.
Maybe the player you mean is Ousmane Dembele not Victor Osimhen, because at this time Viktor Osimhen is playing for Galatasaray in the Turkish league, and he has never played for Barcelona or PSG.
And speaking of Ousmane Dembele, indeed compared to his performance when he was still playing for Barcelona, what Dembele displayed in his second season at PSG, he performed very well and became the main force for PSG for now. He is not only good at scoring a goal but he is also quite good at providing an assist. He always contributes in every match he plays with PSG, be it in the form of goals or assists.
And besides he was able to perform well with PSG, but when he was with the French national team too, he was able to show that indeed he was a truly quality player.