There are too many variables. Not easily done. Local tax laws change and when they do, they change mid-season, secondly they have a jock-tax where they pay taxes in each state they play. Different states have different rules for how these are calculated. Now, a player gets traded from the Rangers to the Red Wings in December. Rangers made their trip to California in November and the player has already played in California for the season. Red Wings do not visit the 3 Cali teams til March. This player's calculation is different than the player coming from the Red Wings to the Rangers.
In NY, the tax rate for someone earning $1,077,550 to $5,000,000 is $72,166 plus 9.65% of the amount over $1,077,550. For someone making $5,000,001-$25,000,000 it is $450,683 plus 10.3% of the amount over $5,000,000. However, it is based on his taxable NY income. Then there are different write-offs, and each person's write-offs are different. I guarantee the money MacKinnon spends on his nutritionist and massage therapist are all written off as business expenses. Realistically speaking, they would need to change the cap to run from Jan 1st-Dec 31st rather season to season and then calculate AFTER either April 15th in the US and whatever tax deadline day in Canada is (if they have one, honestly do not know). Then, you can actually calculate each player's after-tax earnings and determine each team's expenditures, and then calculate whether the players are owed more or have to pay more to escrow. Which in-turn screws up their actual earnings and impacts their tax liabilities the following year.