Firstly, they don't play in the same division, which is a significant factor. Secondly, the Canadiens have many young, inexpensive players and a lot of draft picks, as well as salary cap space.
According to Arpon Basu, it would be very surprising if the Jets' first-round pick, which belongs to the Canadiens from the Sean Monahan trade, remains in Montreal's possession.
Rossi was the 9th overall pick in 2020. He's young and talented, having scored 40 points, including 21 goals, this season. He's ready to reach the next level.
It's certain that if Kent Hughes trades the Jets' pick for him, there will need to be an addition, but that shouldn't be a problem.