Fostering an obligation to dissent
I only had a brief stint in consulting after graduating college, but I use many of the mental models and mindsets from that time to this day. One that has really stuck with me is engraining cultural mindset of an obligation to dissent into the team. That's just a fancy way of saying: If you disagree with something, you have the responsibility to speak up, even you don't want to. Regardless of your seniority in the team.
It is impossible to be a good product manager if your team does not freely speak their mind. You yourself do not need to be a technical expert, but you must understand the key ramifications and how these interact with the rest of the ecosystem. The basis of this is that your team knows that they can speak truth to power and be frank with you.
I try to remain very humble about what I think I know. I want my team to point out the flaws in my thinking, and call out falsities or hypocrisy - I appreciate and am even honored by dissent.
Obligation to dissent encourages people to participate and find the best solution
Dissenters will ask the tough questions, and in the process you are scrutinizing and refining your current path. Every team needs these challengers in the room - what a great boon a diversity of critical thoughts are! I try hard to bake this into the team DNA, because it does take certain confidence to speak up in front of the room. Not all leaders want to hear candid feedback. It takes just one time of belittling a dissenter to alienate the entire team forever. And it's normal to sometimes dearly hope that there won't be dissent, for example when you are strapped for time.
Everyone in the team is an asset - an open environment will make them feel this value. Even if the proposed alternative is not what is chosen, possible weaknesses are being discussed and the team is uniting behind a solution. You will get the best outcomes if people speak their mind. This transparency is also at the heart of scrum.
It is a resistance against groupthink
Groupthink occurs when a group of people avoid friction by attempting to match their opinion to what they think the group consensus is. Dissenters are often - consciously or subconsciously - pressured by the rest of the group to assume the majority opinion. Fostering an obligation to dissent aims to circumvent exactly this. You are normalizing speaking out other PoV's and forcing the team to seriously think about the proposal.
I see this during complexity estimations when there is member putting their finger into the wound of the topic you already spent 45 minutes discussing. It may make some people roll their eyes when the discussion is further elongated, but I am secretly rubbing together my hands in excitement because I feel us nearing a better solution.
Disagree and commit
Maybe the dissenter will stand by his opinion. Now it gets tricky for the decision maker. Dissenting may have a negative connotation. But speaking out against the grain takes guts and is a virtue. It also takes practice.
When my team does not tell me when I am making a mistake - or when they stay silent even when they know things are going sideways - they are being dishonest towards me by omission. It is why this value means so much to me. As the same time: Simply telling your team that they have this obligation will not make it happen. People need to feel secure in order for this to work. That is the prerequisite. And that happens through leadership, which again is molded by the PO. Walk your own talk and positively reinforce your dissenters.