I wouldn’t be hosting or running a marketplace though. My plan is to write the code to make it possible for each individual seller to host/run their own shop that is accessible by anyone else running the same code. The code will be open source, so I’m not sure how I could be sued for any of that. My only involvement would be writing the code.

That also mitigates the problems with a centralized marketplace gaining a bad reputation. Some sellers will definitely cheat the system and those sellers will get a bad reputation, but that is true of anything on the internet. Any website can sell stuff and steal from you technically. Many don’t though because they don’t just want the money from your purchase, but also from all future sales.

I was actually looking to avoid escrow or any of the complicated parts of money handling. My plan was just to click buy, scan the qr code with your own wallet (separate from the marketplace), and then send the funds. The marketplace wouldn’t touch any crypto, and would only interact with it by checking if the funds came in on the seller’s client. That would make it super easy to onboard new sellers and buyers and keep legal stuff completely on the buyers and sellers.