> Some specific advice from that manager was (in his words) "never promise something in 2 weeks unless you could demonstrate it today" and "do not sit quietly when you are given unrealistic timelines; counter with specific subtasks you see and how long you expect each will take".

Thanks these are good advice.

> most managers I had in my now 25-year career in tech were good.

I didn't have tons of managers, but my experience as well. Of course, they have their own interest in mind, rather than mine, but in my case at least, our interests were more or less aligned (completing projects, not burning out or leaving the team, working on things that matter to the company, avoid conflicts...).