I also sell the same products on eBay as Amazon. They are genuine with a significant shelf life, warranty does not apply. I have had very nice buyers, friendlier than Amazon buyers. None complain. Occasionally I will recycle an Amazon box for an eBay order (from fba returns) if it is the best fit. I do try to clean them up of labels, torn tape, etc. My items are new with tags, unless I’m selling fba returns as used condition offers.
My experience as a buyer on eBay has been very positive also. Of course what I sell, how I sell it, and what I buy have a lot to do with the positive interactions.
eBay isn’t all bad. But I do really hate what they did to the Steiner’s.