If it were me and I wasn't willing to DIY, I'd find a local pack builder to put a pack together for me using authentic brand name cells. I personally would not trust any batteries purchased from Aliexpress, Amazon, or Ebay. Counterfeit cells are extremely common and can be difficult to spot even by a trained eye.
It's a lot of money and potentially a lot on the line life and safety wise. Not a good time to bargain hunt. Buy wisely, buy once. IMHO
