This post has a system that can do that by assigning weights to each player. It will need some modification but this would allow you to double the weights of any player who bought the gamepass.
It works by giving every player a weight. Then when it comes to selecting a player it loops through all the weights and with a random number between 1 and the Sum of all the Weights waits till one player’s weight brings that random number from being positive to negative.
This system would work similar to the role selection in Murder Mystery 2 where you are able to increase the chance of a player being selected except it still is random who is picked.