Yes, but half of BYD's cars are hybrid. Only ~1.6M are EV. They've also been around making batteries since 1995 and ICE cars since 2003.

It's not like Tesla's subsidies have been small, but BYD's have been enormous.

As they should have been in both cases. For most uses EV is superior, and this is the only way for Chinese manufacturers to meaningfully tackle the broader markets worldwide. You can’t compete with ICEs and hundreds of billions of dollars invested into that manufacturing capacity, supply chains, and know how. But you can entirely sidestep the whole thing. Which is what the Chinese are doing.

Sounds like a Tesla killing recipe for the existing automotive industry.

How much of a subsidy does Tesla receive by selling its green credits?