iFixit charges a premium but is still stuck buying from the same suppliers as you. I just buy from ebay, or aliexpress. Nothing for the T410 is going to be new new, they're all going to be new old stock at best.
If you really want quality your best bet is to buy an OEM dead battery and rebuild it with your own cells. Just know you'll need to "jump start" the BMS. Crappy 3rd party BMS' don't always require a jump start.