I just started at Meta in the business engineering org (formerly solutions eng). We have a lot of XFN work with sales and SWE teams, so lots of opportunity to coordinate projects and be customer-focused. I was a SWE at my past company but I'm hoping to eventually transition to PM as I believe it is better for upward mobility within a company?
Some quick thoughts from me:
In terms of how to make the transition, you're in luck as I believe that Meta is one of the best companies in the world to make this switch: There is literally a Staff+ engineer archetype at Meta called PM/engineer hybrid. I knew several E6+ engineers back at Instagram that fell into this archetype very cleanly, and I spent a good amount of time investing into this hybrid behavior myself. The obvious path is to become a great engineer that falls into this archetype and then push for the switch. The best way to show that you are qualified for a job is to be already doing it, similar to how lagging promotions work.
In terms of what you can do to start making progress towards this switch:
Lastly, I want to call out that you will probably not be able to do as much PM work as you want since you are an E4:
Alex has given a lot of specific ideas, but I'll give you a more generic answer.
It really depends on your core competency and passion. If you are very interested in a specific function and are good at it, you'll be successful.
If all things were equal, then I would look at the ratio of Eng VPs to PMs. My guess/experience is that there are more Eng VPs than PM VPs? So, the probability of getting to an Eng VP is higher based on pure numbers alone.