AFAIK the Tariff in EU on BYD BEV is 13% (The tariffs vary based on how much state funding the brand has received), but if they have hybrids, they can sell them without tariff. The tariffs are only on BEV.
I dont think their sales would explode if the tariffs were removed. Many people are still cautious about Chinese cars, and some simply don't want a car made in China.
Weird here in Denmark they have a map of dealers on their homepage?
They have dealers pretty well distributred throughout the country.
https://www.bydauto.dk/find-forhandler
Same in Germany:
https://www.byd.com/de/find-store