Ya, the OP is not telling the truth. One there isn't a "variety", second they aren't UL listed at that price. I've spent months researching this space for an off grid setup and these are the two best setups direct from China from a cost standpoint for 15 kWh. Neither are UL listed:

https://www.apexiummall.com/index.php?route=product/product&...

https://yixiangpower.com/products/yixiang-vertical-15kw-diy-...

Both would cost roughly $4800~$5500 for that total size.

If you want good customer service, dependable, UL listed, and correctly priced, then this is the king: https://signaturesolar.com/eg4-wallmount-indoor-battery-48v-...

UL listed ~45 kWh will cost you $10k, not $5.4k.