you could just trick steam to believe the game is updated ;D
once you have game on the version you want... simply winrar it
IF game updates... you simply let it finish and then unwinrar the files afterwards
you replace "new version" with your version and everything works + steam thinks game is updated

it will give you time until next update



also no idea what's the issue on your side
but when I set to not update game unless I laumch it then steam doesn't update it automatically
I have to either force update manually or launch game