Yes, Manchester United is really good right now. But it seems to me that on the contrary, they have been playing better since Ronaldo left the club. But Barcelona is also in the best shape now, ranked number one in Spain and I think the games between Barcelona and Manchester United will be very interesting and unpredictable.
Both teams are in good form right now, and anything can happen in the game.
However, if we compare the last five matches they played together, Manchester United won just one of the five, while Barcelona won the remaining four; and looking at how things happened, both of them were on form at the time they played the match, so there is a possibility of Barcelona winning the game this time again, but everything can happen because Manchester United have new style of play under Ten Hag, so they can win the game as well.