At MS and Amazon, it's more of just timekeeping and making arbitrary changes for job security. I heard Google PM work is more technical and more like a dev lead. How true is that?
I don't think what you said applies to Amazon, probably not for a lot of MS PMs too. At Amazon, PMs tend to be more customer/ business focused afaik.
Then I saw a job posting for Dir of PM - AWS/Redshift, in the requirements, asked for past experience of being Dev Manager. Nothing about PM experience.
The definition and role of a PM depends on the company. My org revolves around PMs as the go-to for client exploration, market facing presentations, product development, marketing, getting funding, shopping for buy in, and then all the "regular" Pm stuff like roadmap.
I have seen google pm corresponding with customers. Definitely not like dev lead