Players pay taxes per game based on the location of the game. Half of the games a player plays will not be subject to their team's local tax laws, but to the laws of the state or province they are playing in.
Players playing in the US get a federal income tax credit for paying state income tax.
Players playing outside of their home country must play additional taxes (to their home country, usually so long as they continue to retain citizenship), but those taxes are prorated based on state and federal income taxes paid in many cases (IE, they pay less taxes to their home country if they pay more in state taxes).
Players have access to tax lawyers and accounts that get paid to minimize their tax burden. Teams also work to do this, especially by maximizing how much time players are doing "chartable" work.
To make your idea work a team will need to know the location of every away game for the next up to 8 years (328 games), the tax laws of each of those places, and if those tax laws will change in that time.
Example: The upper tax brackets had their income tax percentages changed in the US under Trump and may change again under Biden. What happens if a player signs a contract and all of the sudden they need to pay more or less taxes? Many states are considering changing their state income taxes, and some even consider abolishing them. Every player in the NHL's cap hit would need to be adjusted if 1 town that has a hockey team decides to pass an income tax.