My hotter take: All 3 of the engineer, PM and designer will all assume the other 2 are optional, in reality all 3 and the entire company they work for will be optional in most cases.
My hotter take: All 3 of the engineer, PM and designer will all assume the other 2 are optional, in reality all 3 and the entire company they work for will be optional in most cases.
You just need one of them. It's probably the engineer.
Good PMs are not optional. Most PMs are.
How are you defining optional?
Companies without any product managers, much less good ones, are putting out profitable products all the time.