Xbox One X store credit trade in?

I am searching for a store or site that will give me the most trade in credit that, in turn, I can apply towards a Series X preorder. I would assume Gamestop will not file for bankruptcy before the new console comes out. I had a saved trade in credit
but didn’t go and the trade in price dropped significantly. I’m not sure if Microsoft will accept used One X trade ins or not. Is it worth paying for the Gamestop rewards membership because they will give you a percent more than a usual trade in? I buy
1-2 games per year ( only FPS, like Battlefield or Halo) but then buy map packs. I’d use the extra credit from buying the premium Gamestop to get moe for my One X trsde in, buying the Series X, buying a Live membership renewal card/code, and buying a few
games So I’d appreciate advice on maximizing my trade in credit.

:)