I'm curious to learn what kind of challenges you had in your past growth roles. It would be great to understand specific examples/workflows, and how you dealt with them.
For example, we'd have the same opening email sequence, same retargeting, etc. for customers across channels but we'd want to have consistent messaging around offers (ie. "$1000 off when you sign up" vs. "first month free" kind of stuff). It was tricky because we didn't want to advertise the same offer to everyone, so we wanted to carefully segment who was getting which offer and keep it the same over a window of time.
Unfortunately we didn't have a perfect solution. The closest we came to it was to have an experiment ID tied to their user account. Then we had a system where we would define the different experiments (including messaging and promotions) with each experiment having an experiment ID. It was far from perfect but worked.