EVE like CATL, BYD and most others have no interest in dealing with "people" they will only deal with commercial buyers and have an MOQ (Min Order Qty) which is usually high, like 5000 cells at a time. The reality is, the Corporate Demand is more than what supply can support at this time, they have no interest in the ittle guys.
Many vendors sell EVE cells, the vast majority come from Battery Brokers who buy "lots" the end runs, anything that is less than A+ down to "test batch runs" which can be "god knows what". Brokers are also pulling in Used Cells which is China is a LOT.... Remember they have been doing EV's for over a decade, they have the largest BUS FLEETS Globally and they are Electric ! and a LOT MORE, so as a result a lot of decommissioned battery packs and cells are coming into the marketspace there.... AND the Fact that China has lead with LFP for 10+ years and deployed a LOT into EV's it is to be expected.
Very Few Vendors deal directly with Manufacturers, again due to the MOQ's and having to store, manage & ship that all out. Now Amy Wan "Owner of Luyuan" has negotiated with EVE, CATL and buys direct from their supply, they do the Testing & Validation at the Factory, the Matched are indeed Matched & Batched and those that don't make it become the Bulk Cells.
BTW: The IP for LiFePO4 is UP spring 2022, hence factories are being built outside of China to produce LFP. Several of the Battery Recycle Companies like LiCycle & RedWood will also be generating LFP base stock and making that available "locally" as it were.