I'm not the person you asked but I was curious so I looked it up and BYDs sales numbers have previously been under suspicion.
That doesn't prove they were lying then nor does it mean they are lying now.
Also, while BYD's FY2024 revenue was impressive their gross margin fell from 21.9% to 17% and that isn't sustainable now that the tariff headwinds are a blowing.
You can. Nearly all of the "off brand" China produced stuff that's sold at Walmart / Target / Amazon can be purchased online from Ebay, Aliexpress, Temu, etc. The "Name Brand" stuff can often be purchased at the manufacturers website for nearly the same cost as buying it from Amazon or Walmart.