Setting Dependency Dates in Reverse

Okay, our team is a bit lost on what columns to pin down for a new board. We have a board that we are going to use to launch new products. The last pulse is the date to go live and the pulses above are the steps that have to happen before.

We know we have to add the dependency column to get the relationships set up. However, we’re a bit unsure if we need to use the formula column or find a workaround of automations to get the dates set to X # of days before the dependent pulse.

Anyone out there doing something like this that could share their solution? Thx