How can I use external experience (sales for example) to bring different opinions to the table to gain influence and persuade other teams?
Getting a variety of feedback from a variety of people is the best thing you can do to influence and persuade teams. I always like to poll multiple teams and different levels of people to ensure that I have as many examples as possible. Make sure you ask internal teams - sales (including pre-sales and SDRs if you have them), post-sales like customer success and account management, other marketers even - for their input.
Even better try to gather external feedback too if possible. Reach out to friendly customers, ask some of your friends from other companies, schedule an inquiry with a friendly analyst or influencer, the more the merrier! This is especially important for vetting and getting buy in on things like new pricing, messaging for a new product, or a brand new pitch or first call deck.
Once you have some of the feedback documented, you can bring it to the team you are trying to influence and use it to show that you've done your due diligence and truly have something worth considering!
I think you need a mix of experiences AND data to transform what might seem like different opinions into persuasive arguments with impact.
Experiences provide the context and detail, relatable quotes or example customer pain points, etc., and Data provides the measurement - how big of a problem is this? How easily can we quantify it? What impact might it have? That way it can be prioritized.
In your example, perhaps a sales team says "Customers tell us they want this feature / benefit we don't have." with the data, you're also able to say "And we lost X opportunities this month because we don't have it" and perhaps influence the product roadmap or at least the competitive messaging in the short-term.
Having worked well with Product Marketing in the past (and as a sales leader) sales can be admittedly tough to generate buy-in. However, sales is needy and tends to make an overwhelming number of asks from marketing. The problem I've seen is that sales is not educated on the role of product marketing and therefore less supportive. I would start with educating sales on their role/responsibilites, goals & how impactful product marketing "is" or "could be" if they have a strong line of communication. Once they understand how aligned their goals are, it becomes more of a partnership. Sales typically can carry a lot of weight because they are customer facing every day; however, if sales doesn't understand how working closely with marketing will help them move and close more deals then they take the "us" vs. "them" approach. Clear understanding of roles/responsibilites, alignment on goals and the Jerry Maguire "help me, help you."