If OP is comparing their experience in your BYD to Tesla's marketing material, that's not a correct comparison. Tesla battery ranges should generally be derated quite a bit to align them with how the rest of the industry measures range.
And that goes only for rather flat terrain and non-cold environments. Otherwise the discrepancies end up just like consumption of ICE engines in ads vs reality.
Battery is fine by itself, but I'd say that the range is somewhere between 315-350km depending on terrain etc. Definitely not the 420km that's advertised. I knew this beforehand from reviews so it wasn't unexpected, but I'd be pretty angry if I didn't read about it from reviews before I got the car.
For me it's fine as I still only charge once a week and I still have around 70%-80% usually, unless I visit remote relatives. I could probably stretch and recharge every other week if I really wanted to, but I prefer to have it ready as we sometimes do have longer drives.
What are the issues? I thought BYD batteries were as good as they get?
I am pretty sure Teslas sold in my country (NZ) have BYD batteries.