Not specifically addressed to you, but just continuing the conversation. Here's a website that allows to calculate taxes in Canada:
2024 Income Tax Calculator Québec
Very few people pay the top bracket. And for those that might be wondering, the brackets are progressive i.e. on a salary of $100,000 you'd pay 31% in income tax before deductions.
On a salary of $3,750,000, Carrier will pay $1,968,806 in federal and provincial taxes before the deductions that his accountant(s) is sure to get for him. However, since he'll be paid in American dollars and his expenses will be in Canadian dollars, he will get an approximately 33% bonus on his purchasing power. If you also bear in mind that Carrier's health insurance costs will more or less disappear and that properties in Montreal are still quite cheap compared to most North American cities, then suddenly playing in Quebec doesn't seem all that difficult financially.
Montreal wanted a stabilizing presence on a very young blueline, and Trotz wanted to send a message to his players to shape up. The fact Carrier speaks French is just a bonus.