Make legitimate items for sale on these markets and create a place to hide maybe? Maybe even source your bitcoin for dnm purchases and provide cover at the same time. You pay me bitcoin. I order from amazon and ship it to you. No fees. Now I have bitcoin. And you have a black market transaction for a perfectly legal item. Seem like there's potential with some tweaking?
Also ... 2 other thoughts covered many times but sill interesting to me anyway...1) imo ...tumbling and heavy tech opsec for a small time personal use buyer is probably as much a potential snag as the rest of this activity and could make the worst case scenario even worse. And 2) maybe wishful thinking but I can't find any news reports (not reddit throwaway accounts..no offense) of CDs or any other LE action for personal use amounts that didn't seem to involve some other circumstances besides being detected in transit.
I think the information you need to provide to Amazon would be your undoing.
Plus the clear trail of funds...