Have you considered dropping by in person to your nearest computer recycler/refurbisher? As a teen I worked at one, and the boxes and boxes of RAM sticks pulled from scrapped machines (usually scrapped due to bad main boards) made a strong impression. They tend to not even put the highest-spec stuff they pull into anything, as refurbished machines are mostly sold/donated in quantity (to schools and the like) and big customers want standardized SKUs with interchangeable specs for repairability more than they want performance. Workers at these places are often invited to build personal machines to take home out of these “too good” parts — and yet there’s so much that they can’t possibly use it all up that way. If someone showed up asking if they could have some DDR3, they might literally just let you dig through the box and then sell it to you by weight!

We're looking to buy 1TB of DDR5 for a large database server. I'm pretty sure that we're just going to pay the premium and move on.