Heineman seems is doing fine.
Canadiens weekly notebook: Emil Heineman’s role is a big part of his success - The Athletic
"And that’s the other thing. Heineman is a rookie, he’s played every game except one when he sat out the second game of the season in Boston. He’s earned the trust of his coach and his teammates. Everything is going very well, and sometimes when things are going well for a rookie, it might be better to just leave that rookie alone and let him continue to do what he’s doing well.
And Heineman is very happy with how things are going.
“I mean, yeah,” he said with a big smile, “I’m playing in the NHL.”