I recently had a performance review at a FAANG. One engineer on my team has spent the past 3 years working on a complex infrastructure migration which involved about 20 engineers. The migration was completed last year and saved the company some opex costs.

I on the other hand spent 3 weeks optimizing our core service and reduced 2x the opex costs of the large complex 3 year migration.

In my yearly review my manager acknowledged my impact, but said I need to solve more complex problems to get to Staff Engineer. I protested saying that my 3 weeks of work had a larger impact than 20 engineers over 3 years, but he told me that is just how it works.