Similar b2b product exists. What should we do?

You just compete

That's business 101

Better than having no competition. That means their may not be a market.

In B2B experience is CRITICAL. You see young founders for B2C companies, but B2B founders skew much older. Why? Because a rolodex and industry understand is huge.

IMO distribution is all that matters in B2B. If you saw the shitty products many B2B customers use, you'd start building a better product immediately. But they have the account because they've gotten distribution.

I wouldn't worry about other startups if they don't have seasoned people with industry experience.

Competing is so old-world. Operating old-world style is not why we became entrepreneurs. Collaborate, partner, unite, trade strengths, cross-sell, co-market, merge, etc... There are endless possibilities you can create to join forces and win together, one way to find out what those possibilities are: communicate. Have meetings with each of them, be open minded, be vulnerable, and see if there are ways to support each other. In the end you'll end up with relationships with all of them, putting you in a mindset of power and ease.

If the solution is TRULY your passion, see what differentiates your offering and go forward and focus on that. The other startups may not stay the course for the long haul.

First to market or market leader isn't always the best offering on the market.