The fallout from Elon Musk’s plunge into politics a year ago is still hammering his Tesla business as both sales and profits fell sharply again in the latest quarter.

BYD sells BEVs and PHEVs from below $10,000 to $150,000, including its premium Denza, FangChengBao and Yangwang brands, with a steady stream of new or upgraded models. Improved driver-assist systems ...