Comp is meant to stay stable at the agreed upon target for the first two years. There is a cash bonus for years 1 and 2 used to offset the vesting schedule. The final 2 years are really dependent on stock performance. For example, I basically will need AMZN stock to get increase by 25% from todays value by Jan 2025 to be making what I did for the first two years.
From what I've heard, yes they size their Y1 and Y2 cash bonuses such that your TC will be stable over the first 4 years as long as AMZN stock goes up 15%/year.