I would definitely list them on GOAT as well as keeping up the “ buy it now “ listing you have on eBay. Both platforms have thousands of buyers visiting on a daily basis. I would list them a little higher on GOAT though due to the fees they’re going to deduct if they sell. I also stopped doing auctions on fleabay due to non-payment. I always list like you did. A buy it now with a best offer option. You’ll probably get a few lowball offers but you won’t have to deal with someone not paying.
The other thing I like about both platforms is once the shoes pass authentication, you’re obligation is over and you don’t have to worry about buyers remorse / buyer coming back with a complaint or a refund request.