You're dreaming if you think he Cowboys FO is likely to stand still for spending that kind of money to replace Williams. They'd elect to wait 'til the next draft to take someone to replace him for far less. They aren't in any advantageous position in their cap money at this time to make that kind of money expendable. They'll likely wait 'til next year to attend to a solution.
Otherwise, you should look for them to draft a promising rookie guard to fill that spot before considering any LG with experience to replace Williams. Someone like Connor McGovern, whom they already have, could easily be the one to get that done, rather than spending that amount.