That's low-end Zynq and Artix and I'm thinking more >676 Kintex, though I appreciate any discussion on sourcing.

In the way that that Aliexpress vendor lists the 7010 parts at 1/10th the price of LCSC, some of their $20-60 listings are also shockingly cheap in comparison.

Ah, missed the K! For the K420T, I pay around $30-45 from CN (not Aliexpress) sources with original barcodes (but these vendors are quite a bit harder to deal with.)