I was a non-engineering background PM (I dropped out of high school). I can tell you about what I didn't know early in my career that was painful for me then (and something I've internalized hard now): It's ok to say "I don't know". Conversely, saying "I have the answer" when you don't is lying.
The worst thing you can do as a PM is to make a technical assertion that you don't understand to a technical audience. You will instantly lose the audience's respect and trust (and those things are very hard to get back). To my mind, being technical is about actually understanding how things work such that you can make arguments grounded in facts and experience about systems. If you make arguments like "why don't you just rip out Mongo?" without understanding how painful that would be, it's really hard for people to believe in you.
Being non-technical doesn't mean opting out of technical discussions, it just means saying "I don't know" when you don't know. This is something I see PMs screw up all the time.
In reality, nobody knows everything, but pretending you know something when you don't is a verifiable road to hell.
Lastly, product is about two things: intuitive narrative and fact-based decision making. If you can't reason about your product hypotheses from first principles and/or bring established respected metrics to the discussion, you deserve to not be taken seriously.