Welcome to the RX...
You won't find many Sportsbooks that will take a large presidential prop like that.
In most cases they will put a limit on a wager like that, so you will need more than One out ( meaning more than one Book )
I'm going to guess that the Limit ( or Max ) that you found was $500
if so, you would need 10 Books to spread that $5000
Maybe you can find some that will take $1000 max, so that would bring you down to 5 different accounts/books.
Good Luck
