Clarity has dozen's of experts in this area - some are list here:
https://clarity.fm/browse/industries/marketplaces

and here:
https://clarity.fm/topics/marketplaces-10183
https://clarity.fm/topics/online-marketplace-12395

My favorites are
- Micha Kaufman (Founder/CEO @ Fiverr.com) https://clarity.fm/micha
- John Ramey (Founder/CEO of isocket.com) https://clarity.fm/johnramey
- Josh Brelinger (VC, previously #5 @ oDesk.com) https://clarity.fm/jbreinlinger
- Dinesh Thiru (VP of Marketing @ Udemy.com) https://clarity.fm/dinesht
- Fergus Dyer-Smith (Founder/CEO @ Wooshii.com https://clarity.fm/fergusdyer-smith
+ many more.

I may be able to help from my experience founding and building Skillshare, as well as researching marketplaces in general during that time. What specific questions do you have?

Feel free to ping me to setup a call.

Generally, I'd encourage you to check out the Search feature here on Clarity that has a number of featured experts that list where they feel most able to be of help. Check out their reviews and the answers they have submitted to get a good idea of their potential fit with you. Here are a couple of suggestions:

Dan Martell - Founder of Clarity
https://clarity.fm/danmartell

Boris Wertz - Cofounder of AbeBooks which sold to Amazon and an investor in many marketplace companies:
https://clarity.fm/boriswertz

And Elan Mosbacher (I don't know him but his profile looks good) https://clarity.fm/elanmosbacher

Let me know If I can help you. I am working with Yo!Kart online marketplace platform where we help global business owners to launch their own eBay, Etsy, Amazon, or other such marketplaces. I can help you to guide on these topics:

Future of online marketplaces
Different Business models
What are popular revenue channels in an online marketplace
What are the must-have features and functionalities?
How to start with pro active and pre active marketing

Feel free to ping me.

Thank You