Did you just set up your steam account? If so, that's why it wasn't available for you. You had to have already had a steam account set up and a purchase made before June 2021 in order to reserve yesterday.
man wtf?
I woulda been so pissed if I wasted time setting up an account
I was gonna place a hold on it yesterday since it was only $5
but felt it was a waste of time since I have no real intention of buying it soon