The best entry point was probably between € 20-22 last year. The share is just extremely volatile and you definitely have to be very patient. In principle, BYD is a great company with a lot of potential. But the current price would be too high for me... an entry below €30 would be more interesting. And you should never ignore the China risk.
I think the answer depends very much on your investment horizon. In my opinion, they are not suitable for a short-term trade. For me, however, they are the most interesting China stocks in the medium term, together with Xiaomi. I have therefore been investing in both with a share savings plan since January.
I bought byd back then for €20. But the index is dragging the share down. For a good entry, wait for the index to bottom out or buy now and forget about it for 2-3 years.