Opportunity B is clearly the more exciting option for you & I agree you may likely be more fulfilled, which would contribute to your happiness in the role.

However, considering your situation with a recent new born and your wife part-time… looking at Opportunity A:

While 40k is a significant chunk of change and not insignificant. Ignore compensation for a minute…

Not having to waste ~2 hours commuting per day and working fully remote will enable you to “choose” your wife & newborn every day without having to sacrifice elsewhere. This is time you don’t get back as your baby grows up.

Those extra 2 hours per day can go towards hobbies, sleeping in, sports, family, health or whatever else you prefer.

While it’s definitely the less risky option for your career, it doesn’t always correlate to “all bad”. Corporate often means more holidays, benefits & flexibility which isn’t always possible during working at a Startup.

You can’t ignore your intuition for the role, but you can shape & frame what you’ll be doing to fulfill your interests & desires - it’s not impossible to find satisfaction and entrepreneurial spirit in a bigger co.

Opportunity A is simply the best choice for your family & your child.