Indeed, the Slovak has signed for 8 years at $7.6 million per year. This means he will be paid less than his teammates Nick Suzuki and Cole Caufield, despite his high ceiling.
This is also a clear indication that Slaf wants to stay in Montreal and is happy to play for the Canadiens. He could have waited until the end of next season to increase his value, but he preferred to settle this as soon as possible.