Here is my solution to a date stamp for Today’s Date in Deals, similar to the solution by @helenasolsona :
It works well for Deals, but we only have hundreds, not millions.
It would really help to have a Today’s date option built in to the Time Between date calculation properties so we don’t have to use a workaround like this.
I’m hoping HubSpot can make the date calculation options much more robust soon.