Is there any reasonable cost-effective way to import these into the USA? Or is that path blocked due to regulatory safety things?
There are some small exceptions for show cars (as is, never used on public roads) and similar things, but they all limit/prohibit use on public roads.
You're probably, maybe ok for something like a 25 year old full-size car that doesn't look too wild (ie, could pass a a US-spec). Like a Japanese-market Lancer Evo, or Mitsubishi Pajero.
2. Buy a scrapped Tesla in the US.
3. Rebadge the BYD with the Tesla's logos.
4. Bury the Tesla in your yard.
5. Register the rebadged BYD with the Tesla's VIN, slap some plates on it, and drive.