Signing up before or after creating a listing — which performs better?

I'm working on a marketplace site where a user can be a buyer, a seller, or both. Right now I'm focusing on onboarding from a seller's perspective. Think about sites like AirBnB, Ebay, or Etsy, where the the homepage is primarily targeting buyers, but there's still a link or CTA aimed at sellers to "become a seller" or "list your item." That's the flow I'm questioning right now.

Should the onboarding flow for an owner start with A. creating their listing and then signing up, or B. creating an account and then creating their listing.

My gut instinct is that option A is the better flow, as it keeps them focused on the task they want to accomplish, which is selling something. And then only after they've already invested time in creating their listing (which the are personally motivated to do because they want to earn money) do we hit them with the sign up form. At which point, they've already come so far and how could they say no.

However, looking at some other marketplace sites, a lot of them go with option B. Their seller CTA starts by asking the user to create an account first, and then lets them create their listing. I could assume the positives here are getting the user to create an account and grab their contact information ASAP. And if the user falls off at any point during the listing process, they can log in and continue where they left off.

Some sites that use option A: kickstarter.com fatlama.com ebay.com

Some sites that use option B: airbnb.com etsy.com

Does anyone here have an opinion on one flow over the other? Of course this would be such a great thing to A/B test, but creating two entirely different flows seems like a heavy lift and I'm not sure if I'd be able to sell my managers on it.