its a simple fix. Both teams get a possession. Who ever has more points after both teams have a possession wins. If its a tie THEN it becomes sudden death. So KC scores TD first. Then Bills would get the ball. If the Bills score a TD they can decide to go for 2 and win or extra point and try sudden death. Fair way to do it. Whats the downside of that?
The downside is that it’s the same problem with the current set of rules: The winner of the coin toss gets the undeserved advantage of being able to win the game with an extra possession not afforded to the team that loss the coin toss. Since the coin toss is purely luck, it shouldn’t have an appreciable effect on who wins the game (individual circumstances notwithstanding).
The simple solution would be to have two possessions, and if it’s tied after two possessions, then repeat until one team is leading after an even amount of possessions. Similar to the college rules, except none of that gimmicky give the teams the ball at the 25 yard line BS.
(And really, by possession, I mean a chance at a possession, so failing to recover an onside kick or muffing a punt results in a forfeiture of your possession)